Reinstantiate EditableTextHandler instance on focus change.

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 435 matching lines @@
     new Output().withSpeechAndBraille(
             this.currentRange_, prevRange, evt.type)
         .go();
   },
 
   /**
    * 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;
 
     // It almost never makes sense to place focus directly on a rootWebArea.
     if (node.role == RoleType.rootWebArea) {
       // 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.
@@ skipping 72 matching lines @@
         true);  // triggered by user
     if (!this.editableTextHandler ||
         evt.target != this.currentRange_.start.node) {
       this.editableTextHandler =
           new cvox.ChromeVoxEditableTextBase(
               textChangeEvent.value,
               textChangeEvent.start,
               textChangeEvent.end,
               evt.target.state['protected'],
               cvox.ChromeVox.tts);
+
+      // Ignore the first text selection changed event which gets fired after

[dmazzoni, 2015/09/10 18:46:41]

This shouldn't be necessary once https://codereview.chromium.org/1318683002/
lands

+      // the focus event.
+      return;
     }
 
     this.editableTextHandler.changed(textChangeEvent);
     new Output().withBraille(
             this.currentRange_, null, evt.type)
         .go();
   },
 
   /**
    * Provides all feedback once a value changed event fires.
@@ skipping 181 matching lines @@
       var start = text.getSpanStart(selectionSpan);
       actionNode.setSelection(position - start, position - start);
     }
   }
 };
 
 /** @type {Background} */
 global.backgroundObj = new Background();
 
 });  // goog.scope