Work around <webview> focus bugs by enforcing focus event invariants.

chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview The entry point for all ChromeVox2 related code for the
  * background page.
  */
 
 goog.provide('Background');
@@ skipping 465 matching lines @@
   /**
    * Provides all feedback once a focus event fires.
    * @param {Object} evt
    */
   onFocus: function(evt) {
     // Invalidate any previous editable text handler state.
     this.editableTextHandler_ = null;
 
     var node = evt.target;
 
+
+    // Discard focus events on embeddedObject nodes.
+    if (node.role == RoleType.embeddedObject)
+      return;
+
     // It almost never makes sense to place focus directly on a rootWebArea.
     if (node.role == RoleType.rootWebArea) {
+      // Discard focus events for root web areas when focus was previously
+      // placed on a descendant.
+      if (this.currentRange_.start.node.root == node)
+        return;
+
+      // Discard focused root nodes without focused state set.
+      if (!node.state.focused)
+        return;
+
       // Try to find a focusable descendant.
-      node = AutomationUtil.findNodePost(node,
-                                         Dir.FORWARD,
-                                         AutomationPredicate.focused) || node;
-
-      // Fall back to the first leaf node in the document.
-      if (node.role == RoleType.rootWebArea) {
-        node = AutomationUtil.findNodePost(node,
-                                           Dir.FORWARD,
-                                           AutomationPredicate.leaf);
-      }
+      node = node.find({state: {focused: true}}) || node;
     }
 
     if (evt.target.role == RoleType.textField)
       this.createEditableTextHandlerIfNeeded_(evt.target);
 
     this.onEventDefault({target: node, type: 'focus'});
   },
 
   /**
    * Provides all feedback once a load complete event fires.
@@ skipping 42 matching lines @@
    */
   onTextOrTextSelectionChanged: function(evt) {
     // Don't process nodes inside of web content if ChromeVox Next is inactive.
     if (evt.target.root.role != RoleType.desktop &&
         this.mode_ === ChromeVoxMode.CLASSIC)
       return;
 
     if (!evt.target.state.focused)
       return;
 
+    if (evt.target.role != RoleType.textField)
+      return;
+
     if (!this.currentRange_) {
       this.onEventDefault(evt);
       this.currentRange_ = cursors.Range.fromNode(evt.target);
     }
 
     this.createEditableTextHandlerIfNeeded_(evt.target);
     var textChangeEvent = new cvox.TextChangeEvent(
         evt.target.value,
         evt.target.textSelStart,
         evt.target.textSelEnd,
@@ skipping 220 matching lines @@
               node.state.protected,
               cvox.ChromeVox.tts);
     }
   }
 };
 
 /** @type {Background} */
 global.backgroundObj = new Background();
 
 });  // goog.scope