Enable the full accessibility tree experiment by default

Based on DevTools + Chrome Accessibility + Blink>DOM team's discussions, we have decidede to turn on the experiment by default first, since there
is no critical bugs in this experiment, and we want to collect more user feedback before moving it out of the experimental status.

Context: https://docs.google.com/document/d/1wRSaHV88zLoK_acQJD4O4auOkq-9FmpoAN-cjTStYO0/edit?tab=t.0#heading=h.lwx7tsz9x51w

Bug: 40808541
Change-Id: I76f548e53bf2a6b5d97911347e247e6b3d2d958b
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6233912
Auto-Submit: Changhao Han <[email protected]>
Reviewed-by: Benedikt Meurer <[email protected]>
Commit-Queue: Benedikt Meurer <[email protected]>

Author: hanselfmu-chromium

front_end/entrypoints/main/MainImpl.ts

@@ -412,6 +412,7 @@ export class MainImpl {
       Root.Runtime.ExperimentName.TIMELINE_ALTERNATIVE_NAVIGATION,
       Root.Runtime.ExperimentName.TIMELINE_THIRD_PARTY_DEPENDENCIES,
       Root.Runtime.ExperimentName.TIMELINE_DIM_UNRELATED_EVENTS,
+      Root.Runtime.ExperimentName.FULL_ACCESSIBILITY_TREE,
       ...(Root.Runtime.Runtime.queryParam('isChromeForTesting') ? ['protocol-monitor'] : []),
     ]);
 

front_end/panels/elements/AccessibilityTreeView.test.ts

@@ -26,7 +26,9 @@ describeWithMockConnection('AccessibilityTreeView', () => {
 
   const updatesUiOnEvent = (inScope: boolean) => async () => {
     SDK.TargetManager.TargetManager.instance().setScopeTarget(inScope ? target : null);
-    new Elements.AccessibilityTreeView.AccessibilityTreeView(toggleButoon, treeComponent);
+    const view = new Elements.AccessibilityTreeView.AccessibilityTreeView(toggleButoon, treeComponent);
+    view.markAsRoot();
+    view.show(document.body);
 
     const model = target.model(SDK.AccessibilityModel.AccessibilityModel);
     const treeComponentDataSet = sinon.spy(treeComponent, 'data', ['set']);

front_end/panels/elements/AccessibilityTreeView.ts

@@ -147,6 +147,9 @@ export class AccessibilityTreeView extends UI.Widget.VBox implements
   treeUpdated({data}: Common.EventTarget
                   .EventTargetEvent<SDK.AccessibilityModel.EventTypes[SDK.AccessibilityModel.Events.TREE_UPDATED]>):
       void {
+    if (!this.isShowing()) {
+      return;
+    }
     if (!data.root) {
       void this.renderTree();
       return;

test/e2e/helpers/elements-helpers.ts

@@ -962,7 +962,6 @@ function veImpressionForAccessibilityPane() {
             'Section', 'accessibility-tree',
             [
               veImpression('Toggle', 'full-accessibility-tree'),
-              veImpression('TreeItem', undefined, [veImpression('Expand'), veImpression('TreeItem')]),
             ]),
         veImpression('SectionHeader', 'aria-attributes'),
         veImpression('Section', 'aria-attributes'),