[PM-11517] Improve autofill collection of page details performance (#10816)

* Testing out a rework of the performance improvements introduced into extension

* Working through improvements

* Implementing max_depth methodology for the deepQuery approach used when querying elements

* Refactoring implementation

* Refactoring implementation

* Fixing jest tests

* Incorporating documenation within domQueryService

* [PM-11519] `browser` global reference triggering an error when sending an extension message

* [PM-11517] Working through refactoring and jest testing of the domQueryService

* [PM-11517] Working through refactoring and jest testing of the domQueryService

* [PM-11517] Incorporating tests for the debounce util method

* [PM-11517] Incorporating tests for the debounce util method

* [PM-11517] Removing unnecessary property

* [PM-11517] Starting to work through an idea regarding querying without the shadowDom on pages that definitively do not contain a ShadowDOM element

* [PM-11419] Adjusting implementation to ensure we clear any active requests when the passkeys setting is modified

* [PM-11517] Removing unnecessary comments

apps/browser/src/autofill/content/auto-submit-login.spec.ts

@@ -5,23 +5,17 @@ import {
   createAutofillPageDetailsMock,
   createAutofillScriptMock,
 } from "../spec/autofill-mocks";
-import { flushPromises, sendMockExtensionMessage } from "../spec/testing-utils";
+import {
+  flushPromises,
+  mockQuerySelectorAllDefinedCall,
+  sendMockExtensionMessage,
+} from "../spec/testing-utils";
 import { FormFieldElement } from "../types";
 
 let pageDetailsMock: AutofillPageDetails;
 let fillScriptMock: AutofillScript;
 let autofillFieldElementByOpidMock: FormFieldElement;
 
-jest.mock("../services/dom-query.service", () => {
-  const module = jest.requireActual("../services/dom-query.service");
-  return {
-    DomQueryService: class extends module.DomQueryService {
-      deepQueryElements<T>(element: HTMLElement, queryString: string): T[] {
-        return Array.from(element.querySelectorAll(queryString)) as T[];
-      }
-    },
-  };
-});
 jest.mock("../services/collect-autofill-content.service", () => {
   const module = jest.requireActual("../services/collect-autofill-content.service");
   return {
@@ -47,6 +41,8 @@ jest.mock("../services/collect-autofill-content.service", () => {
 jest.mock("../services/insert-autofill-content.service");
 
 describe("AutoSubmitLogin content script", () => {
+  const mockQuerySelectorAll = mockQuerySelectorAllDefinedCall();
+
   beforeEach(() => {
     jest.useFakeTimers();
     setupEnvironmentDefaults();
@@ -60,6 +56,7 @@ describe("AutoSubmitLogin content script", () => {
 
   afterAll(() => {
     jest.clearAllMocks();
+    mockQuerySelectorAll.mockRestore();
   });
 
   it("ends the auto-submit login workflow if the page does not contain any fields", async () => {

apps/browser/src/autofill/content/auto-submit-login.ts

@@ -10,7 +10,9 @@ import InsertAutofillContentService from "../services/insert-autofill-content.se
 import {
   elementIsInputElement,
   getSubmitButtonKeywordsSet,
+  nodeIsButtonElement,
   nodeIsFormElement,
+  nodeIsTypeSubmitElement,
   sendExtensionMessage,
 } from "../utils";
 
@@ -189,13 +191,21 @@ import {
     element: HTMLElement,
     lastFieldIsPasswordInput = false,
   ): boolean {
-    const genericSubmitElement = querySubmitButtonElement(element, "[type='submit']");
+    const genericSubmitElement = querySubmitButtonElement(
+      element,
+      "[type='submit']",
+      (node: Node) => nodeIsTypeSubmitElement(node),
+    );
     if (genericSubmitElement) {
       clickSubmitElement(genericSubmitElement, lastFieldIsPasswordInput);
       return true;
     }
 
-    const buttonElement = querySubmitButtonElement(element, "button, [type='button']");
+    const buttonElement = querySubmitButtonElement(
+      element,
+      "button, [type='button']",
+      (node: Node) => nodeIsButtonElement(node),
+    );
     if (buttonElement) {
       clickSubmitElement(buttonElement, lastFieldIsPasswordInput);
       return true;
@@ -210,11 +220,17 @@ import {
    *
    * @param element - The element to query for submit buttons
    * @param selector - The selector to query for submit buttons
+   * @param treeWalkerFilter - The callback used to filter treeWalker results
    */
-  function querySubmitButtonElement(element: HTMLElement, selector: string) {
+  function querySubmitButtonElement(
-    const submitButtonElements = domQueryService.deepQueryElements<HTMLButtonElement>(
+    element: HTMLElement,
+    selector: string,
+    treeWalkerFilter: CallableFunction,
+  ) {
+    const submitButtonElements = domQueryService.query<HTMLButtonElement>(
       element,
       selector,
+      treeWalkerFilter,
     );
     for (let index = 0; index < submitButtonElements.length; index++) {
       const submitElement = submitButtonElements[index];
@@ -272,20 +288,11 @@ import {
    * Gets all form elements on the page.
    */
   function getAutofillFormElements(): HTMLFormElement[] {
-    const formElements: HTMLFormElement[] = [];
+    return domQueryService.query<HTMLFormElement>(
-    domQueryService.queryAllTreeWalkerNodes(
       globalContext.document.documentElement,
-      (node: Node) => {
+      "form",
-        if (nodeIsFormElement(node)) {
+      (node: Node) => nodeIsFormElement(node),
-          formElements.push(node);
-          return true;
-        }
-
-        return false;
-      },
     );
-
-    return formElements;
   }
 
   /**

apps/browser/src/autofill/content/autofill-init.ts

@@ -38,7 +38,7 @@ class AutofillInit implements AutofillInitInterface {
    * @param overlayNotificationsContentService - The overlay notifications content service, potentially undefined.
    */
   constructor(
-    private domQueryService: DomQueryService,
+    domQueryService: DomQueryService,
     private autofillOverlayContentService?: AutofillOverlayContentService,
     private autofillInlineMenuContentService?: AutofillInlineMenuContentService,
     private overlayNotificationsContentService?: OverlayNotificationsContentService,

apps/browser/src/autofill/services/abstractions/dom-query.service.ts

@@ -1,12 +1,11 @@
 export interface DomQueryService {
-  deepQueryElements<T>(
+  query<T>(
     root: Document | ShadowRoot | Element,
     queryString: string,
+    treeWalkerFilter: CallableFunction,
     mutationObserver?: MutationObserver,
+    forceDeepQueryAttempt?: boolean,
   ): T[];
-  queryAllTreeWalkerNodes(
+  checkPageContainsShadowDom(): void;
-    rootNode: Node,
+  pageContainsShadowDomElements(): boolean;
-    filterCallback: CallableFunction,
-    mutationObserver?: MutationObserver,
-  ): Node[];
 }

apps/browser/src/autofill/services/autofill-overlay-content.service.ts

@@ -32,6 +32,8 @@ import {
   elementIsFillableFormField,
   elementIsSelectElement,
   getAttributeBoolean,
+  nodeIsButtonElement,
+  nodeIsTypeSubmitElement,
   sendExtensionMessage,
   throttle,
 } from "../utils";
@@ -508,12 +510,20 @@ export class AutofillOverlayContentService implements AutofillOverlayContentServ
    * @param element - The element to find the submit button within.
    */
   private findSubmitButton(element: HTMLElement): HTMLElement | null {
-    const genericSubmitElement = this.querySubmitButtonElement(element, "[type='submit']");
+    const genericSubmitElement = this.querySubmitButtonElement(
+      element,
+      "[type='submit']",
+      (node: Node) => nodeIsTypeSubmitElement(node),
+    );
     if (genericSubmitElement) {
       return genericSubmitElement;
     }
 
-    const submitButtonElement = this.querySubmitButtonElement(element, "button, [type='button']");
+    const submitButtonElement = this.querySubmitButtonElement(
+      element,
+      "button, [type='button']",
+      (node: Node) => nodeIsButtonElement(node),
+    );
     if (submitButtonElement) {
       return submitButtonElement;
     }
@@ -524,11 +534,17 @@ export class AutofillOverlayContentService implements AutofillOverlayContentServ
    *
    * @param element - The element to query for a submit button.
    * @param selector - The selector to use to query the element for a submit button.
+   * @param treeWalkerFilter - The tree walker filter to use when querying the element.
    */
-  private querySubmitButtonElement(element: HTMLElement, selector: string) {
+  private querySubmitButtonElement(
-    const submitButtonElements = this.domQueryService.deepQueryElements<HTMLButtonElement>(
+    element: HTMLElement,
+    selector: string,
+    treeWalkerFilter: CallableFunction,
+  ) {
+    const submitButtonElements = this.domQueryService.query<HTMLButtonElement>(
       element,
       selector,
+      treeWalkerFilter,
     );
     for (let index = 0; index < submitButtonElements.length; index++) {
       const submitElement = submitButtonElements[index];

apps/browser/src/autofill/services/collect-autofill-content.service.spec.ts

@@ -17,6 +17,14 @@ import { CollectAutofillContentService } from "./collect-autofill-content.servic
 import DomElementVisibilityService from "./dom-element-visibility.service";
 import { DomQueryService } from "./dom-query.service";
 
+jest.mock("../utils", () => {
+  const utils = jest.requireActual("../utils");
+  return {
+    ...utils,
+    debounce: jest.fn((fn) => fn),
+  };
+});
+
 const mockLoginForm = `
   <div id="root">
     <form>
@@ -29,6 +37,7 @@ const mockLoginForm = `
 const waitForIdleCallback = () => new Promise((resolve) => globalThis.requestIdleCallback(resolve));
 
 describe("CollectAutofillContentService", () => {
+  const mockQuerySelectorAll = mockQuerySelectorAllDefinedCall();
   const domElementVisibilityService = new DomElementVisibilityService();
   const inlineMenuFieldQualificationService = mock<InlineMenuFieldQualificationService>();
   const domQueryService = new DomQueryService();
@@ -38,7 +47,6 @@ describe("CollectAutofillContentService", () => {
   );
   let collectAutofillContentService: CollectAutofillContentService;
   const mockIntersectionObserver = mock<IntersectionObserver>();
-  const mockQuerySelectorAll = mockQuerySelectorAllDefinedCall();
 
   beforeEach(() => {
     globalThis.requestIdleCallback = jest.fn((cb, options) => setTimeout(cb, 100));
@@ -55,6 +63,7 @@ describe("CollectAutofillContentService", () => {
   afterEach(() => {
     jest.clearAllMocks();
     jest.restoreAllMocks();
+    jest.clearAllTimers();
     document.body.innerHTML = "";
   });
 
@@ -2001,41 +2010,6 @@ describe("CollectAutofillContentService", () => {
     });
   });
 
-  describe("getShadowRoot", () => {
-    beforeEach(() => {
-      // eslint-disable-next-line
-      // @ts-ignore
-      globalThis.chrome.dom = {
-        openOrClosedShadowRoot: jest.fn(),
-      };
-    });
-
-    it("returns null if the passed node is not an HTMLElement instance", () => {
-      const textNode = document.createTextNode("Hello, world!");
-      const shadowRoot = collectAutofillContentService["getShadowRoot"](textNode);
-
-      expect(shadowRoot).toEqual(null);
-    });
-
-    it("returns an open shadow root if the passed node has a shadowDOM element", () => {
-      const element = document.createElement("div");
-      element.attachShadow({ mode: "open" });
-
-      const shadowRoot = collectAutofillContentService["getShadowRoot"](element);
-
-      expect(shadowRoot).toBeInstanceOf(ShadowRoot);
-    });
-
-    it("returns a value provided by Chrome's openOrClosedShadowRoot API", () => {
-      const element = document.createElement("div");
-      collectAutofillContentService["getShadowRoot"](element);
-
-      // eslint-disable-next-line
-      // @ts-ignore
-      expect(chrome.dom.openOrClosedShadowRoot).toBeCalled();
-    });
-  });
-
   describe("setupMutationObserver", () => {
     it("sets up a mutation observer and observes the document element", () => {
       jest.spyOn(MutationObserver.prototype, "observe");
@@ -2048,6 +2022,12 @@ describe("CollectAutofillContentService", () => {
   });
 
   describe("handleMutationObserverMutation", () => {
+    const waitForAllMutationsToComplete = async () => {
+      await waitForIdleCallback();
+      await waitForIdleCallback();
+      await waitForIdleCallback();
+    };
+
     it("will set the domRecentlyMutated value to true and the noFieldsFound value to false if a form or field node has been added ", async () => {
       const form = document.createElement("form");
       document.body.appendChild(form);
@@ -2071,7 +2051,7 @@ describe("CollectAutofillContentService", () => {
       jest.spyOn(collectAutofillContentService as any, "isAutofillElementNodeMutated");
 
       collectAutofillContentService["handleMutationObserverMutation"]([mutationRecord]);
-      await waitForIdleCallback();
+      await waitForAllMutationsToComplete();
 
       expect(collectAutofillContentService["domRecentlyMutated"]).toEqual(true);
       expect(collectAutofillContentService["noFieldsFound"]).toEqual(false);
@@ -2115,7 +2095,7 @@ describe("CollectAutofillContentService", () => {
           target: document.body,
         },
       ]);
-      await waitForIdleCallback();
+      await waitForAllMutationsToComplete();
 
       expect(collectAutofillContentService["_autofillFormElements"].size).toEqual(0);
       expect(collectAutofillContentService["autofillFieldElements"].size).toEqual(0);
@@ -2140,7 +2120,7 @@ describe("CollectAutofillContentService", () => {
       jest.spyOn(collectAutofillContentService as any, "handleAutofillElementAttributeMutation");
 
       collectAutofillContentService["handleMutationObserverMutation"]([mutationRecord]);
-      await waitForIdleCallback();
+      await waitForAllMutationsToComplete();
 
       expect(collectAutofillContentService["domRecentlyMutated"]).toEqual(false);
       expect(collectAutofillContentService["noFieldsFound"]).toEqual(true);

apps/browser/src/autofill/services/collect-autofill-content.service.ts

@@ -20,6 +20,7 @@ import {
   getPropertyOrAttribute,
   requestIdleCallbackPolyfill,
   cancelIdleCallbackPolyfill,
+  debounce,
 } from "../utils";
 
 import { AutofillOverlayContentService } from "./abstractions/autofill-overlay-content.service";
@@ -57,7 +58,6 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
     "image",
     "file",
   ]);
-  private useTreeWalkerStrategyFlagSet = true;
 
   constructor(
     private domElementVisibilityService: DomElementVisibilityService,
@@ -69,11 +69,6 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
       inputQuery += `:not([type="${type}"])`;
     }
     this.formFieldQueryString = `${inputQuery}, textarea:not([data-bwignore]), select:not([data-bwignore]), span[data-bwautofill]`;
-
-    // void sendExtensionMessage("getUseTreeWalkerApiForPageDetailsCollectionFeatureFlag").then(
-    //   (useTreeWalkerStrategyFlag) =>
-    //     (this.useTreeWalkerStrategyFlagSet = !!useTreeWalkerStrategyFlag?.result),
-    // );
   }
 
   get autofillFormElements(): AutofillFormElements {
@@ -297,13 +292,12 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
   ): FormFieldElement[] {
     let formFieldElements = previouslyFoundFormFieldElements;
     if (!formFieldElements) {
-      formFieldElements = this.useTreeWalkerStrategyFlagSet
+      formFieldElements = this.domQueryService.query<FormFieldElement>(
-        ? this.queryTreeWalkerForAutofillFormFieldElements()
+        globalThis.document.documentElement,
-        : this.domQueryService.deepQueryElements(
+        this.formFieldQueryString,
-            document,
+        (node: Node) => this.isNodeFormFieldElement(node),
-            this.formFieldQueryString,
+        this.mutationObserver,
-            this.mutationObserver,
+      );
-          );
     }
 
     if (!fieldsLimit || formFieldElements.length <= fieldsLimit) {
@@ -836,17 +830,32 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
     formElements: HTMLFormElement[];
     formFieldElements: FormFieldElement[];
   } {
-    if (this.useTreeWalkerStrategyFlagSet) {
-      return this.queryTreeWalkerForAutofillFormAndFieldElements();
-    }
-
-    const queriedElements = this.domQueryService.deepQueryElements<HTMLElement>(
-      document,
-      `form, ${this.formFieldQueryString}`,
-      this.mutationObserver,
-    );
     const formElements: HTMLFormElement[] = [];
     const formFieldElements: FormFieldElement[] = [];
+
+    const queriedElements = this.domQueryService.query<HTMLElement>(
+      globalThis.document.documentElement,
+      `form, ${this.formFieldQueryString}`,
+      (node: Node) => {
+        if (nodeIsFormElement(node)) {
+          formElements.push(node);
+          return true;
+        }
+
+        if (this.isNodeFormFieldElement(node)) {
+          formFieldElements.push(node as FormFieldElement);
+          return true;
+        }
+
+        return false;
+      },
+      this.mutationObserver,
+    );
+
+    if (formElements.length || formFieldElements.length) {
+      return { formElements, formFieldElements };
+    }
+
     for (let index = 0; index < queriedElements.length; index++) {
       const element = queriedElements[index];
       if (elementIsFormElement(element)) {
@@ -891,34 +900,6 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
     return this.nonInputFormFieldTags.has(nodeTagName) && !nodeHasBwIgnoreAttribute;
   }
 
-  /**
-   * Attempts to get the ShadowRoot of the passed node. If support for the
-   * extension based openOrClosedShadowRoot API is available, it will be used.
-   * Will return null if the node is not an HTMLElement or if the node has
-   * child nodes.
-   *
-   * @param {Node} node
-   */
-  private getShadowRoot(node: Node): ShadowRoot | null {
-    if (!nodeIsElement(node)) {
-      return null;
-    }
-
-    if (node.shadowRoot) {
-      return node.shadowRoot;
-    }
-
-    if ((chrome as any).dom?.openOrClosedShadowRoot) {
-      try {
-        return (chrome as any).dom.openOrClosedShadowRoot(node);
-      } catch (error) {
-        return null;
-      }
-    }
-
-    return (node as any).openOrClosedShadowRoot;
-  }
-
   /**
    * Sets up a mutation observer on the body of the document. Observes changes to
    * DOM elements to ensure we have an updated set of autofill field data.
@@ -948,7 +929,7 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
     }
 
     if (!this.mutationsQueue.length) {
-      requestIdleCallbackPolyfill(this.processMutations, { timeout: 500 });
+      requestIdleCallbackPolyfill(debounce(this.processMutations, 100), { timeout: 500 });
     }
     this.mutationsQueue.push(mutations);
   };
@@ -979,41 +960,62 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
    * within an idle callback to help with performance and prevent excessive updates.
    */
   private processMutations = () => {
-    for (let queueIndex = 0; queueIndex < this.mutationsQueue.length; queueIndex++) {
+    const queueLength = this.mutationsQueue.length;
-      this.processMutationRecord(this.mutationsQueue[queueIndex]);
+
+    if (!this.domQueryService.pageContainsShadowDomElements()) {
+      this.domQueryService.checkPageContainsShadowDom();
     }
 
-    if (this.domRecentlyMutated) {
+    for (let queueIndex = 0; queueIndex < queueLength; queueIndex++) {
-      this.updateAutofillElementsAfterMutation();
+      const mutations = this.mutationsQueue[queueIndex];
+      const processMutationRecords = () => {
+        this.processMutationRecords(mutations);
+
+        if (queueIndex === queueLength - 1 && this.domRecentlyMutated) {
+          this.updateAutofillElementsAfterMutation();
+        }
+      };
+
+      requestIdleCallbackPolyfill(processMutationRecords, { timeout: 500 });
     }
 
     this.mutationsQueue = [];
   };
 
   /**
-   * Processes a mutation record and updates the autofill elements if necessary.
+   * Processes all mutation records encountered by the mutation observer.
    *
    * @param mutations - The mutation record to process
    */
-  private processMutationRecord(mutations: MutationRecord[]) {
+  private processMutationRecords(mutations: MutationRecord[]) {
     for (let mutationIndex = 0; mutationIndex < mutations.length; mutationIndex++) {
-      const mutation = mutations[mutationIndex];
+      const mutation: MutationRecord = mutations[mutationIndex];
-      if (
+      const processMutationRecord = () => this.processMutationRecord(mutation);
-        mutation.type === "childList" &&
+      requestIdleCallbackPolyfill(processMutationRecord, { timeout: 500 });
-        (this.isAutofillElementNodeMutated(mutation.removedNodes, true) ||
+    }
-          this.isAutofillElementNodeMutated(mutation.addedNodes))
+  }
-      ) {
-        this.domRecentlyMutated = true;
-        if (this.autofillOverlayContentService) {
-          this.autofillOverlayContentService.pageDetailsUpdateRequired = true;
-        }
-        this.noFieldsFound = false;
-        continue;
-      }
 
-      if (mutation.type === "attributes") {
+  /**
-        this.handleAutofillElementAttributeMutation(mutation);
+   * Processes a single mutation record and updates the autofill elements if necessary.
+   * @param mutation
+   * @private
+   */
+  private processMutationRecord(mutation: MutationRecord) {
+    if (
+      mutation.type === "childList" &&
+      (this.isAutofillElementNodeMutated(mutation.removedNodes, true) ||
+        this.isAutofillElementNodeMutated(mutation.addedNodes))
+    ) {
+      this.domRecentlyMutated = true;
+      if (this.autofillOverlayContentService) {
+        this.autofillOverlayContentService.pageDetailsUpdateRequired = true;
       }
+      this.noFieldsFound = false;
+      return;
+    }
+
+    if (mutation.type === "attributes") {
+      this.handleAutofillElementAttributeMutation(mutation);
     }
   }
 
@@ -1036,20 +1038,19 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
         continue;
       }
 
-      if (
+      if (nodeIsFormElement(node) || this.isNodeFormFieldElement(node)) {
-        !this.useTreeWalkerStrategyFlagSet &&
-        (nodeIsFormElement(node) || this.isNodeFormFieldElement(node))
-      ) {
         mutatedElements.push(node as HTMLElement);
       }
 
-      const autofillElements = this.useTreeWalkerStrategyFlagSet
+      const autofillElements = this.domQueryService.query<HTMLElement>(
-        ? this.queryTreeWalkerForMutatedElements(node)
+        node,
-        : this.domQueryService.deepQueryElements<HTMLElement>(
+        `form, ${this.formFieldQueryString}`,
-            node,
+        (walkerNode: Node) =>
-            `form, ${this.formFieldQueryString}`,
+          nodeIsFormElement(walkerNode) || this.isNodeFormFieldElement(walkerNode),
-            this.mutationObserver,
+        this.mutationObserver,
-          );
+        true,
+      );
+
       if (autofillElements.length) {
         mutatedElements = mutatedElements.concat(autofillElements);
       }
@@ -1083,19 +1084,20 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
   private setupOverlayListenersOnMutatedElements(mutatedElements: Node[]) {
     for (let elementIndex = 0; elementIndex < mutatedElements.length; elementIndex++) {
       const node = mutatedElements[elementIndex];
-      if (
+      const buildAutofillFieldItem = () => {
-        !this.isNodeFormFieldElement(node) ||
+        if (
-        this.autofillFieldElements.get(node as ElementWithOpId<FormFieldElement>)
+          !this.isNodeFormFieldElement(node) ||
-      ) {
+          this.autofillFieldElements.get(node as ElementWithOpId<FormFieldElement>)
-        continue;
+        ) {
-      }
+          return;
+        }
 
-      requestIdleCallbackPolyfill(
         // We are setting this item to a -1 index because we do not know its position in the DOM.
         // This value should be updated with the next call to collect page details.
-        () => void this.buildAutofillFieldItem(node as ElementWithOpId<FormFieldElement>, -1),
+        void this.buildAutofillFieldItem(node as ElementWithOpId<FormFieldElement>, -1);
-        { timeout: 1000 },
+      };
-      );
+
+      requestIdleCallbackPolyfill(buildAutofillFieldItem, { timeout: 1000 });
     }
   }
 
@@ -1367,6 +1369,19 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
     }
   }
 
+  /**
+   * Validates whether a password field is within the document.
+   */
+  isPasswordFieldWithinDocument(): boolean {
+    return (
+      this.domQueryService.query<HTMLInputElement>(
+        globalThis.document.documentElement,
+        `input[type="password"]`,
+        (node: Node) => nodeIsInputElement(node) && node.type === "password",
+      )?.length > 0
+    );
+  }
+
   /**
    * Destroys the CollectAutofillContentService. Clears all
    * timeouts and disconnects the mutation observer.
@@ -1378,84 +1393,4 @@ export class CollectAutofillContentService implements CollectAutofillContentServ
     this.mutationObserver?.disconnect();
     this.intersectionObserver?.disconnect();
   }
-
-  /**
-   * @deprecated - This method remains as a fallback in the case that the deepQuery implementation fails.
-   */
-  private queryTreeWalkerForAutofillFormAndFieldElements(): {
-    formElements: HTMLFormElement[];
-    formFieldElements: FormFieldElement[];
-  } {
-    const formElements: HTMLFormElement[] = [];
-    const formFieldElements: FormFieldElement[] = [];
-    this.domQueryService.queryAllTreeWalkerNodes(
-      document.documentElement,
-      (node: Node) => {
-        if (nodeIsFormElement(node)) {
-          formElements.push(node);
-          return true;
-        }
-
-        if (this.isNodeFormFieldElement(node)) {
-          formFieldElements.push(node as FormFieldElement);
-          return true;
-        }
-
-        return false;
-      },
-      this.mutationObserver,
-    );
-
-    return { formElements, formFieldElements };
-  }
-
-  /**
-   * @deprecated - This method remains as a fallback in the case that the deepQuery implementation fails.
-   */
-  private queryTreeWalkerForAutofillFormFieldElements(): FormFieldElement[] {
-    return this.domQueryService.queryAllTreeWalkerNodes(
-      document.documentElement,
-      (node: Node) => this.isNodeFormFieldElement(node),
-      this.mutationObserver,
-    ) as FormFieldElement[];
-  }
-
-  /**
-   * @deprecated - This method remains as a fallback in the case that the deepQuery implementation fails.
-   *
-   * @param node - The node to query
-   */
-  private queryTreeWalkerForMutatedElements(node: Node): HTMLElement[] {
-    return this.domQueryService.queryAllTreeWalkerNodes(
-      node,
-      (walkerNode: Node) =>
-        nodeIsFormElement(walkerNode) || this.isNodeFormFieldElement(walkerNode),
-      this.mutationObserver,
-    ) as HTMLElement[];
-  }
-
-  /**
-   * @deprecated - This method remains as a fallback in the case that the deepQuery implementation fails.
-   */
-  private queryTreeWalkerForPasswordElements(): HTMLElement[] {
-    return this.domQueryService.queryAllTreeWalkerNodes(
-      document.documentElement,
-      (node: Node) => nodeIsInputElement(node) && node.type === "password",
-    ) as HTMLElement[];
-  }
-
-  /**
-   * This is a temporary method to maintain a fallback strategy for the tree walker API
-   *
-   * @deprecated - This method remains as a fallback in the case that the deepQuery implementation fails.
-   */
-  isPasswordFieldWithinDocument(): boolean {
-    if (this.useTreeWalkerStrategyFlagSet) {
-      return Boolean(this.queryTreeWalkerForPasswordElements()?.length);
-    }
-
-    return Boolean(
-      this.domQueryService.deepQueryElements(document, `input[type="password"]`)?.length,
-    );
-  }
 }

apps/browser/src/autofill/services/dom-query.service.spec.ts

@@ -1,21 +1,60 @@
-import { mockQuerySelectorAllDefinedCall } from "../spec/testing-utils";
+import { flushPromises, mockQuerySelectorAllDefinedCall } from "../spec/testing-utils";
 
 import { DomQueryService } from "./dom-query.service";
 
+jest.mock("../utils", () => {
+  const actualUtils = jest.requireActual("../utils");
+  return {
+    ...actualUtils,
+    sendExtensionMessage: jest.fn((command, options) => {
+      if (command === "getUseTreeWalkerApiForPageDetailsCollectionFeatureFlag") {
+        return Promise.resolve({ result: false });
+      }
+
+      return chrome.runtime.sendMessage(Object.assign({ command }, options));
+    }),
+  };
+});
+
 describe("DomQueryService", () => {
+  const originalDocumentReadyState = document.readyState;
   let domQueryService: DomQueryService;
   let mutationObserver: MutationObserver;
   const mockQuerySelectorAll = mockQuerySelectorAllDefinedCall();
 
-  beforeEach(() => {
+  beforeEach(async () => {
-    domQueryService = new DomQueryService();
     mutationObserver = new MutationObserver(() => {});
+    domQueryService = new DomQueryService();
+    await flushPromises();
+  });
+
+  afterEach(() => {
+    Object.defineProperty(document, "readyState", {
+      value: originalDocumentReadyState,
+      writable: true,
+    });
   });
 
   afterAll(() => {
     mockQuerySelectorAll.mockRestore();
   });
 
+  it("checks the page content for shadow DOM elements after the page has completed loading", async () => {
+    Object.defineProperty(document, "readyState", {
+      value: "loading",
+      writable: true,
+    });
+    jest.spyOn(globalThis, "addEventListener");
+
+    const domQueryService = new DomQueryService();
+    await flushPromises();
+
+    expect(globalThis.addEventListener).toHaveBeenCalledWith(
+      "load",
+      domQueryService["checkPageContainsShadowDom"],
+    );
+  });
+
   describe("deepQueryElements", () => {
     it("queries form field elements that are nested within a ShadowDOM", () => {
       const root = document.createElement("div");
@@ -26,9 +65,10 @@ describe("DomQueryService", () => {
       form.appendChild(input);
       shadowRoot.appendChild(form);
 
-      const formFieldElements = domQueryService.deepQueryElements(
+      const formFieldElements = domQueryService.query(
         shadowRoot,
         "input",
+        (element: Element) => element.tagName === "INPUT",
         mutationObserver,
       );
 
@@ -36,6 +76,7 @@ describe("DomQueryService", () => {
     });
 
     it("queries form field elements that are nested within multiple ShadowDOM elements", () => {
+      domQueryService["pageContainsShadowDom"] = true;
       const root = document.createElement("div");
       const shadowRoot1 = root.attachShadow({ mode: "open" });
       const root2 = document.createElement("div");
@@ -47,18 +88,50 @@ describe("DomQueryService", () => {
       shadowRoot2.appendChild(form);
       shadowRoot1.appendChild(root2);
 
-      const formFieldElements = domQueryService.deepQueryElements(
+      const formFieldElements = domQueryService.query(
         shadowRoot1,
         "input",
+        (element: Element) => element.tagName === "INPUT",
         mutationObserver,
       );
 
       expect(formFieldElements).toStrictEqual([input]);
     });
+
+    it("will fallback to using the TreeWalker API if a depth larger than 4 ShadowDOM elements is encountered", () => {
+      domQueryService["pageContainsShadowDom"] = true;
+      const root = document.createElement("div");
+      const shadowRoot1 = root.attachShadow({ mode: "open" });
+      const root2 = document.createElement("div");
+      const shadowRoot2 = root2.attachShadow({ mode: "open" });
+      const root3 = document.createElement("div");
+      const shadowRoot3 = root3.attachShadow({ mode: "open" });
+      const root4 = document.createElement("div");
+      const shadowRoot4 = root4.attachShadow({ mode: "open" });
+      const root5 = document.createElement("div");
+      const shadowRoot5 = root5.attachShadow({ mode: "open" });
+      const form = document.createElement("form");
+      const input = document.createElement("input");
+      input.type = "text";
+      form.appendChild(input);
+      shadowRoot5.appendChild(form);
+      shadowRoot4.appendChild(root5);
+      shadowRoot3.appendChild(root4);
+      shadowRoot2.appendChild(root3);
+      shadowRoot1.appendChild(root2);
+      const treeWalkerCallback = jest
+        .fn()
+        .mockImplementation(() => (element: Element) => element.tagName === "INPUT");
+
+      domQueryService.query(shadowRoot1, "input", treeWalkerCallback, mutationObserver);
+
+      expect(treeWalkerCallback).toHaveBeenCalled();
+    });
   });
 
   describe("queryAllTreeWalkerNodes", () => {
     it("queries form field elements that are nested within multiple ShadowDOM elements", () => {
+      domQueryService["pageContainsShadowDom"] = true;
       const root = document.createElement("div");
       const shadowRoot1 = root.attachShadow({ mode: "open" });
       const root2 = document.createElement("div");
@@ -70,8 +143,9 @@ describe("DomQueryService", () => {
       shadowRoot2.appendChild(form);
       shadowRoot1.appendChild(root2);
 
-      const formFieldElements = domQueryService.queryAllTreeWalkerNodes(
+      const formFieldElements = domQueryService.query(
         shadowRoot1,
+        "input",
         (element: Element) => element.tagName === "INPUT",
         mutationObserver,
       );

apps/browser/src/autofill/services/dom-query.service.ts

@@ -1,8 +1,77 @@
-import { nodeIsElement } from "../utils";
+import { EVENTS, MAX_DEEP_QUERY_RECURSION_DEPTH } from "@bitwarden/common/autofill/constants";
+
+import { nodeIsElement, sendExtensionMessage } from "../utils";
 
 import { DomQueryService as DomQueryServiceInterface } from "./abstractions/dom-query.service";
 
 export class DomQueryService implements DomQueryServiceInterface {
+  private pageContainsShadowDom: boolean;
+  private useTreeWalkerStrategyFlagSet = true;
+
+  constructor() {
+    void this.init();
+  }
+
+  /**
+   * Sets up a query that will trigger a deepQuery of the DOM, querying all elements that match the given query string.
+   * If the deepQuery fails or reaches a max recursion depth, it will fall back to a treeWalker query.
+   *
+   * @param root - The root element to start the query from
+   * @param queryString - The query string to match elements against
+   * @param treeWalkerFilter - The filter callback to use for the treeWalker query
+   * @param mutationObserver - The MutationObserver to use for observing shadow roots
+   * @param forceDeepQueryAttempt - Whether to force a deep query attempt
+   */
+  query<T>(
+    root: Document | ShadowRoot | Element,
+    queryString: string,
+    treeWalkerFilter: CallableFunction,
+    mutationObserver?: MutationObserver,
+    forceDeepQueryAttempt?: boolean,
+  ): T[] {
+    if (!forceDeepQueryAttempt && this.pageContainsShadowDomElements()) {
+      return this.queryAllTreeWalkerNodes<T>(root, treeWalkerFilter, mutationObserver);
+    }
+
+    try {
+      return this.deepQueryElements<T>(root, queryString, mutationObserver);
+    } catch {
+      return this.queryAllTreeWalkerNodes<T>(root, treeWalkerFilter, mutationObserver);
+    }
+  }
+
+  /**
+   * Checks if the page contains any shadow DOM elements.
+   */
+  checkPageContainsShadowDom = (): void => {
+    this.pageContainsShadowDom = this.queryShadowRoots(globalThis.document.body, true).length > 0;
+  };
+
+  /**
+   * Determines whether to use the treeWalker strategy for querying the DOM.
+   */
+  pageContainsShadowDomElements(): boolean {
+    return this.useTreeWalkerStrategyFlagSet || this.pageContainsShadowDom;
+  }
+
+  /**
+   * Initializes the DomQueryService, checking for the presence of shadow DOM elements on the page.
+   */
+  private async init() {
+    const useTreeWalkerStrategyFlag = await sendExtensionMessage(
+      "getUseTreeWalkerApiForPageDetailsCollectionFeatureFlag",
+    );
+    if (useTreeWalkerStrategyFlag && typeof useTreeWalkerStrategyFlag.result === "boolean") {
+      this.useTreeWalkerStrategyFlagSet = useTreeWalkerStrategyFlag.result;
+    }
+
+    if (globalThis.document.readyState === "complete") {
+      this.checkPageContainsShadowDom();
+      return;
+    }
+    globalThis.addEventListener(EVENTS.LOAD, this.checkPageContainsShadowDom);
+  }
+
   /**
    * Queries all elements in the DOM that match the given query string.
    * Also, recursively queries all shadow roots for the element.
@@ -11,16 +80,25 @@ export class DomQueryService implements DomQueryServiceInterface {
    * @param queryString - The query string to match elements against
    * @param mutationObserver - The MutationObserver to use for observing shadow roots
    */
-  deepQueryElements<T>(
+  private deepQueryElements<T>(
     root: Document | ShadowRoot | Element,
     queryString: string,
     mutationObserver?: MutationObserver,
   ): T[] {
     let elements = this.queryElements<T>(root, queryString);
-    const shadowRoots = this.recursivelyQueryShadowRoots(root, mutationObserver);
+
+    const shadowRoots = this.recursivelyQueryShadowRoots(root);
     for (let index = 0; index < shadowRoots.length; index++) {
       const shadowRoot = shadowRoots[index];
       elements = elements.concat(this.queryElements<T>(shadowRoot, queryString));
+
+      if (mutationObserver) {
+        mutationObserver.observe(shadowRoot, {
+          attributes: true,
+          childList: true,
+          subtree: true,
+        });
+      }
     }
 
     return elements;
@@ -46,23 +124,24 @@ export class DomQueryService implements DomQueryServiceInterface {
    * `isObservingShadowRoot` parameter is set to true.
    *
    * @param root - The root element to start the query from
-   * @param mutationObserver - The MutationObserver to use for observing shadow roots
+   * @param depth - The depth of the recursion
    */
   private recursivelyQueryShadowRoots(
     root: Document | ShadowRoot | Element,
-    mutationObserver?: MutationObserver,
+    depth: number = 0,
   ): ShadowRoot[] {
+    if (!this.pageContainsShadowDom) {
+      return [];
+    }
+
+    if (depth >= MAX_DEEP_QUERY_RECURSION_DEPTH) {
+      throw new Error("Max recursion depth reached");
+    }
+
     let shadowRoots = this.queryShadowRoots(root);
     for (let index = 0; index < shadowRoots.length; index++) {
       const shadowRoot = shadowRoots[index];
-      shadowRoots = shadowRoots.concat(this.recursivelyQueryShadowRoots(shadowRoot));
+      shadowRoots = shadowRoots.concat(this.recursivelyQueryShadowRoots(shadowRoot, depth + 1));
-      if (mutationObserver) {
-        mutationObserver.observe(shadowRoot, {
-          attributes: true,
-          childList: true,
-          subtree: true,
-        });
-      }
     }
 
     return shadowRoots;
@@ -72,14 +151,23 @@ export class DomQueryService implements DomQueryServiceInterface {
    * Queries any immediate shadow roots found within the given root element.
    *
    * @param root - The root element to start the query from
+   * @param returnSingleShadowRoot - Whether to return a single shadow root or an array of shadow roots
    */
-  private queryShadowRoots(root: Document | ShadowRoot | Element): ShadowRoot[] {
+  private queryShadowRoots(
+    root: Document | ShadowRoot | Element,
+    returnSingleShadowRoot = false,
+  ): ShadowRoot[] {
     const shadowRoots: ShadowRoot[] = [];
     const potentialShadowRoots = root.querySelectorAll(":defined");
     for (let index = 0; index < potentialShadowRoots.length; index++) {
       const shadowRoot = this.getShadowRoot(potentialShadowRoots[index]);
-      if (shadowRoot) {
+      if (!shadowRoot) {
-        shadowRoots.push(shadowRoot);
+        continue;
+      }
+
+      shadowRoots.push(shadowRoot);
+      if (returnSingleShadowRoot) {
+        break;
       }
     }
 
@@ -121,12 +209,12 @@ export class DomQueryService implements DomQueryServiceInterface {
    * @param filterCallback
    * @param mutationObserver
    */
-  queryAllTreeWalkerNodes(
+  private queryAllTreeWalkerNodes<T>(
     rootNode: Node,
     filterCallback: CallableFunction,
     mutationObserver?: MutationObserver,
-  ): Node[] {
+  ): T[] {
-    const treeWalkerQueryResults: Node[] = [];
+    const treeWalkerQueryResults: T[] = [];
 
     this.buildTreeWalkerNodesQueryResults(
       rootNode,
@@ -147,9 +235,9 @@ export class DomQueryService implements DomQueryServiceInterface {
    * @param filterCallback
    * @param mutationObserver
    */
-  private buildTreeWalkerNodesQueryResults(
+  private buildTreeWalkerNodesQueryResults<T>(
     rootNode: Node,
-    treeWalkerQueryResults: Node[],
+    treeWalkerQueryResults: T[],
     filterCallback: CallableFunction,
     mutationObserver?: MutationObserver,
   ) {
@@ -158,7 +246,7 @@ export class DomQueryService implements DomQueryServiceInterface {
 
     while (currentNode) {
       if (filterCallback(currentNode)) {
-        treeWalkerQueryResults.push(currentNode);
+        treeWalkerQueryResults.push(currentNode as T);
       }
 
       const nodeShadowRoot = this.getShadowRoot(currentNode);

apps/browser/src/autofill/services/insert-autofill-content.service.spec.ts

@@ -68,6 +68,7 @@ function setMockWindowLocation({
 }
 
 describe("InsertAutofillContentService", () => {
+  const mockQuerySelectorAll = mockQuerySelectorAllDefinedCall();
   const inlineMenuFieldQualificationService = mock<InlineMenuFieldQualificationService>();
   const domQueryService = new DomQueryService();
   const domElementVisibilityService = new DomElementVisibilityService();
@@ -82,7 +83,6 @@ describe("InsertAutofillContentService", () => {
   );
   let insertAutofillContentService: InsertAutofillContentService;
   let fillScript: AutofillScript;
-  const mockQuerySelectorAll = mockQuerySelectorAllDefinedCall();
 
   beforeEach(() => {
     document.body.innerHTML = mockLoginForm;

apps/browser/src/autofill/spec/testing-utils.ts

@@ -176,7 +176,7 @@ export function triggerWebRequestOnCompletedEvent(details: chrome.webRequest.Web
 
 export function mockQuerySelectorAllDefinedCall() {
   const originalDocumentQuerySelectorAll = document.querySelectorAll;
-  document.querySelectorAll = function (selector: string) {
+  globalThis.document.querySelectorAll = function (selector: string) {
     return originalDocumentQuerySelectorAll.call(
       document,
       selector === ":defined" ? "*" : selector,

apps/browser/src/autofill/utils/index.spec.ts

@@ -10,6 +10,7 @@ import {
   setElementStyles,
   setupExtensionDisconnectAction,
   setupAutofillInitDisconnectAction,
+  debounce,
 } from "./index";
 
 describe("buildSvgDomElement", () => {
@@ -211,3 +212,35 @@ describe("setupAutofillInitDisconnectAction", () => {
     expect(window.bitwardenAutofillInit).toBeUndefined();
   });
 });
+
+describe("debounce", () => {
+  const debouncedFunction = jest.fn();
+  const debounced = debounce(debouncedFunction, 100);
+
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  afterEach(() => {
+    jest.clearAllTimers();
+  });
+
+  afterAll(() => {
+    jest.useRealTimers();
+  });
+
+  it("does not call the method until the delay is complete", () => {
+    debounced();
+    jest.advanceTimersByTime(50);
+    expect(debouncedFunction).not.toHaveBeenCalled();
+  });
+
+  it("calls the method a single time when the debounce is triggered multiple times", () => {
+    debounced();
+    debounced();
+    debounced();
+    jest.advanceTimersByTime(100);
+
+    expect(debouncedFunction).toHaveBeenCalledTimes(1);
+  });
+});

apps/browser/src/autofill/utils/index.ts

@@ -311,6 +311,18 @@ export function nodeIsFormElement(node: Node): node is HTMLFormElement {
   return nodeIsElement(node) && elementIsFormElement(node);
 }
 
+export function nodeIsTypeSubmitElement(node: Node): node is HTMLElement {
+  return nodeIsElement(node) && getPropertyOrAttribute(node as HTMLElement, "type") === "submit";
+}
+
+export function nodeIsButtonElement(node: Node): node is HTMLButtonElement {
+  return (
+    nodeIsElement(node) &&
+    (elementIsInstanceOf<HTMLButtonElement>(node, "button") ||
+      getPropertyOrAttribute(node as HTMLElement, "type") === "button")
+  );
+}
+
 /**
  * Returns a boolean representing the attribute value of an element.
  *
@@ -361,6 +373,20 @@ export function throttle(callback: (_args: any) => any, limit: number) {
   };
 }
 
+/**
+ * Debounces a callback function to run after a delay of `delay` milliseconds.
+ *
+ * @param callback - The callback function to debounce.
+ * @param delay - The time in milliseconds to debounce the callback.
+ */
+export function debounce(callback: (_args: any) => any, delay: number) {
+  let timeout: NodeJS.Timeout;
+  return function (...args: unknown[]) {
+    globalThis.clearTimeout(timeout);
+    timeout = globalThis.setTimeout(() => callback.apply(this, args), delay);
+  };
+}
+
 /**
  * Gathers and normalizes keywords from a potential submit button element. Used
  * to verify if the element submits a login or change password form.

libs/common/src/autofill/constants/index.ts

@@ -107,3 +107,5 @@ export const ExtensionCommand = {
 export type ExtensionCommandType = (typeof ExtensionCommand)[keyof typeof ExtensionCommand];
 
 export const CLEAR_NOTIFICATION_LOGIN_DATA_DURATION = 60 * 1000; // 1 minute
+
+export const MAX_DEEP_QUERY_RECURSION_DEPTH = 4;