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

chrome/browser/resources/chromeos/chromevox/common/braille_util_test.unitjs

 // 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.
 
 // Include test fixture.
 GEN_INCLUDE(['../testing/chromevox_unittest_base.js']);
 
 /**
  * Test fixture.
  * @constructor
  * @extends {ChromeVoxUnitTestBase}
  */
 function CvoxBrailleUtilUnitTest() {}
 
 CvoxBrailleUtilUnitTest.prototype = {
   __proto__: ChromeVoxUnitTestBase.prototype,
 
   /** @override */
   closureModuleDeps: [
     'cvox.BrailleUtil',
     'cvox.CursorSelection',
     'cvox.NavigationShifter',
-    'cvox.TestMsgs',
+    'TestMsgs',
   ],
 
   /** @override */
   setUp: function() {
-    cvox.ChromeVox.msgs = new cvox.TestMsgs();
+    Msgs = TestMsgs;
   },
 
   /**
    * @param {!Node} expectedParent Expected parent node.
    * @param {!Node} node Node to examine.
    * @private
    */
   assertTextNodeChildOf_: function(expectedParent, node) {
     assertEquals(Node.TEXT_NODE, node.nodeType);
     assertEquals(expectedParent, node.parentNode);
@@ skipping 372 matching lines @@
   selectionSpan = s.getSpanInstanceOf(cvox.ValueSelectionSpan);
   assertEquals(5, s.getSpanStart(selectionSpan));
   assertEquals(5, s.getSpanEnd(selectionSpan));
 
   // All of the value selected selected with reversed start and end.
   s = cvox.BrailleUtil.createValue('value', 5, 0);
   selectionSpan = s.getSpanInstanceOf(cvox.ValueSelectionSpan);
   assertEquals(0, s.getSpanStart(selectionSpan));
   assertEquals(5, s.getSpanEnd(selectionSpan));
 });