Don't update range on LiveRegionUpdated.

This is a follow-up of httep://crrev/c/1964835.

This changes
1. rename DesktopAutomationHandler.onEventFromView to
   onLiveRegionChanged because this method is now not only from Views
   but also from ARC's live region change.

2. When LIVE_REGION_CHANGED event is handled, do not uodate focus range.

Bug: none
Change-Id: I2923e217f0177395bb5e2e4b7b34726a9408ccce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2056168
Commit-Queue: Hiroki Sato <hirokisato@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742503}

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

@@ -16,9 +16,7 @@ goog.require('CustomAutomationEvent');
 goog.require('editing.TextEditHandler');
 
 goog.scope(function() {
-const AutomationEvent = chrome.automation.AutomationEvent;
 const AutomationNode = chrome.automation.AutomationNode;
-const Dir = constants.Dir;
 const EventType = chrome.automation.EventType;
 const RoleType = chrome.automation.RoleType;
 const StateType = chrome.automation.StateType;
@@ -66,7 +64,7 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
     // Note that live region changes from views are really announcement
     // events. Their target nodes contain no live region semantics and have no
     // relation to live regions which are supported in |LiveRegions|.
-    this.addListener_(EventType.LIVE_REGION_CHANGED, this.onEventFromViews);
+    this.addListener_(EventType.LIVE_REGION_CHANGED, this.onLiveRegionChanged);
 
     this.addListener_(EventType.LOAD_COMPLETE, this.onLoadComplete);
     this.addListener_(EventType.MENU_END, this.onMenuEnd);
@@ -100,16 +98,6 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
     return false;
   }
 
-  /**
-   * @param {!ChromeVoxEvent} evt
-   */
-  onEventFromViews(evt) {
-    if (evt.target.root.role == RoleType.DESKTOP ||
-        evt.target.root.role == RoleType.APPLICATION) {
-      this.onEventDefault(evt);
-    }
-  }
-
   /**
    * Handles the result of a hit test.
    * @param {!AutomationNode} node The hit result.
@@ -293,6 +281,32 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
     this.createTextEditHandlerIfNeeded_(node);
   }
 
+  /**
+   * @param {!ChromeVoxEvent} evt
+   */
+  onLiveRegionChanged(evt) {
+    if (evt.target.root.role == RoleType.DESKTOP ||
+        evt.target.root.role == RoleType.APPLICATION) {
+      if (evt.target.containerLiveStatus != 'assertive' &&
+          evt.target.containerLiveStatus != 'polite') {
+        return;
+      }
+
+      const output = new Output();
+      if (evt.target.containerLiveStatus == 'assertive') {
+        output.withQueueMode(QueueMode.CATEGORY_FLUSH);
+      } else {
+        output.withQueueMode(QueueMode.QUEUE);
+      }
+
+      output
+          .withRichSpeechAndBraille(
+              cursors.Range.fromNode(evt.target), null, evt.type)
+          .withSpeechCategory(TtsCategory.LIVE)
+          .go();
+    }
+  }
+
   /**
    * Provides all feedback once a load complete event fires.
    * @param {!ChromeVoxEvent} evt