Expand Chrome OS ARC support to create one tree source per package

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

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js
index d698bb099177025774d6970a6778a933a4395465..4873e593f7b8681489fbdcd33e1eebff479fb536 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js
@@ -51,6 +51,8 @@ DesktopAutomationHandler = function(node) {
                     this.onAriaAttributeChanged);
   this.addListener_(EventType.AUTOCORRECTION_OCCURED,
                     this.onEventIfInRange);
+  this.addListener_(EventType.BLUR,
+                    this.onBlur);
   this.addListener_(EventType.CHECKED_STATE_CHANGED,
                     this.onCheckedStateChanged);
   this.addListener_(EventType.CHILDREN_CHANGED,
@@ -243,6 +245,14 @@ DesktopAutomationHandler.prototype = {
     new Output().withSpeechAndBraille(range, null, evt.type).go();
   },
 
+  onBlur: function(evt) {
+    // Nullify focus if it no longer exists.
+    chrome.automation.getFocus(function(focus) {
+      if (!focus)
+        ChromeVoxState.instance.setCurrentRange(null);
+    });
+  },
+
   /**
    * Provides all feedback once a checked state changed event fires.
    * @param {!AutomationEvent} evt