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

chrome/browser/resources/chromeos/chromevox/walkers/layout_line_walker_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 CvoxLayoutLineWalkerUnitTest() {}
 
 CvoxLayoutLineWalkerUnitTest.prototype = {
   __proto__: ChromeVoxUnitTestBase.prototype,
 
   /** @override */
   closureModuleDeps: [
+    'TestMsgs',
     'cvox.CursorSelection',
     'cvox.LayoutLineWalker',
-    'cvox.TestMsgs',
   ],
 
   /** @override */
   setUp: function() {
     this.loadHtml(
      '<div id="1">' +
       '<p id="a">Demonstrating that in-line links like ' +
         '<a id="aa" href="google.com">google</a> ' +
         'are considered a single layout line.' +
       '</p>' +
       '<p id="b">' +
         'This includes a paragraph that has a lot of text like this one. ' +
         '<a id="bb" href="wikipedia.com">Wikipedia</a> ' +
         'is a great example of a site that this walker becomes valuable.<br>' +
         'Braille also benefits greatly from this type of formatting since ' +
         'some displays can handle lots of text like 80 cell displays!' +
       '</p>' +
      '</div>'
     );
-    cvox.ChromeVox.msgs = new cvox.TestMsgs();
+    Msgs = TestMsgs;
     this.walker = new cvox.LayoutLineWalker();
   
     this.a = cvox.CursorSelection.fromNode($('a'));
     this.aa = cvox.CursorSelection.fromNode($('aa'));
     this.b = cvox.CursorSelection.fromNode($('b'));
     this.bb = cvox.CursorSelection.fromNode($('bb'));
   
     this.line1Text = 'Demonstrating that in-line links like google are' +
         ' considered a single layout line.';
   
@@ skipping 117 matching lines @@
 
   // First line.
   sel = this.walker.next(sel);
   assertEquals(this.line1Text, sel.getText());
 
   // Wrap.
   sel.setReversed(true);
   sel = this.walker.next(sel);
   assertEquals(null, sel);
 });