Improve braille related message descriptions and clean up message handling in Chromevox.

chrome/browser/resources/chromeos/chromevox/common/page_selection.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 A class representing a DOM selection conveyed through
  * CursorSelection idioms.
  * A PageSelection is just a DOM selection. The class itself manages a single
  * CursorSelection that surrounds a fragment on the page. It also provides an
  * extend operation to either grow or shrink the selection given a
@@ skipping 27 matching lines @@
  * navigation.
  * @param {!cvox.CursorSelection} curSel Current CursorSelection in navigation.
  * @return {Array<cvox.NavDescription>} The new description.
  */
 cvox.PageSelection.prototype.getDescription =
     function(navShifter, prevSel, curSel) {
   var desc = [];
   if (this.sel_.isReversed() != curSel.isReversed()) {
     // A shrinking selection.
     desc = navShifter.getDescription(curSel, prevSel);
-    desc[0].annotation = cvox.ChromeVox.msgs.getMsg('describe_unselected');
+    desc[0].annotation = Msgs.getMsg('describe_unselected');
     desc[0].pushEarcon(cvox.Earcon.SELECTION_REVERSE);
   } else {
     // A growing selection.
     desc = navShifter.getDescription(prevSel, curSel);
-    desc[0].annotation = cvox.ChromeVox.msgs.getMsg('describe_selected');
+    desc[0].annotation = Msgs.getMsg('describe_selected');
     desc[0].pushEarcon(cvox.Earcon.SELECTION);
     if (!this.wasBegin_ && this.sel_.absEquals(curSel.clone().normalize())) {
       // A selection has inverted across the start cursor. Describe it.
       var prevDesc = navShifter.getDescription(curSel, prevSel);
       prevDesc[0].annotation =
-          cvox.ChromeVox.msgs.getMsg('describe_unselected');
+          Msgs.getMsg('describe_unselected');
       prevDesc[0].pushEarcon(cvox.Earcon.SELECTION_REVERSE);
       prevDesc[0].pushEarcon(cvox.Earcon.WRAP);
       desc = prevDesc.concat(desc);
     }
   }
   return desc;
 };
 
 
 /**
  * Gets a full description for the entire DOM selection.
  * Use this description when you want to describe the entire selection
  * represented by this instance.
  *
  * @return {Array<cvox.NavDescription>} The new description.
  */
 cvox.PageSelection.prototype.getFullDescription = function() {
   return [new cvox.NavDescription(
       {text: window.getSelection().toString(),
-       context: cvox.ChromeVox.msgs.getMsg('selection_is')})];
+       context: Msgs.getMsg('selection_is')})];
 };
 
 
 /**
  * Extends this selection.
  * @param {!cvox.CursorSelection} sel Extend DOM selection to the selection.
  * @return {boolean} True if the extension occurred, false if the PageSelection
  * was reset to sel.
  */
 cvox.PageSelection.prototype.extend = function(sel) {
   if (!this.sel_.directedBefore(sel)) {
     // Do not allow for crossed selections. This restarts a page selection that
     // has been collapsed. This occurs when two CursorSelection's point away
     // from one another.
     this.sel_ = sel.clone();
   } else {
     // Otherwise, it is assumed that the CursorSelection's are in directed
     // document order. The CursorSelection's are either pointing in the same
     // direction or towards one another. In the first case, shrink/extend this
     // PageSelection to the end of "sel". In the second case, shrink/extend this
     // PageSelection to the start of "sel".
     this.sel_.end = this.sel_.isReversed() == sel.isReversed() ?
         sel.end.clone() : sel.start.clone();
   }
   this.sel_.select();
   this.wasBegin_ = false;
   return !this.sel_.absEquals(sel);
 };