Add ChromeVox panel and implement caption display functionality.

chrome/browser/resources/chromeos/chromevox/braille/braille_display_manager.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 Puts text on a braille display.
  *
  */
 
 goog.provide('cvox.BrailleDisplayManager');
@@ skipping 177 matching lines @@
 /** @private */
 cvox.BrailleDisplayManager.prototype.refresh_ = function() {
   if (!this.displayState_.available) {
     return;
   }
   var viewPort = this.panStrategy_.viewPort;
   var buf = this.displayedContent_.slice(viewPort.start, viewPort.end);
   if (this.realDisplayState_.available) {
     chrome.brailleDisplayPrivate.writeDots(buf);
   }
+
+  var start = this.brailleToTextPosition_(viewPort.start);
+  var end = this.brailleToTextPosition_(viewPort.end);
+  var brailleText = this.content_.text.toString().substring(start, end);
   if (cvox.BrailleCaptionsBackground.isEnabled()) {
-    var start = this.brailleToTextPosition_(viewPort.start);
-    var end = this.brailleToTextPosition_(viewPort.end);
-    cvox.BrailleCaptionsBackground.setContent(
-        this.content_.text.toString().substring(start, end), buf);
+    cvox.BrailleCaptionsBackground.setContent(brailleText, buf);

[Peter Lundblad, 2015/11/06 15:00:57]

What's the point of this change?

[dmazzoni, 2015/11/06 21:01:00]

Oops, I originally tried hooking into this file to drive the braille captions
but changed my mind. Reverted this change.

   }
 };
 
 
 /**
  * @param {!cvox.NavBraille} newContent New display content.
  * @param {cvox.ExpandingBrailleTranslator.ExpansionType} newExpansionType
  *     How the value part of of the new content should be expanded
  *     with regards to contractions.
  * @private
@@ skipping 173 matching lines @@
  */
 cvox.BrailleDisplayManager.prototype.updatePanStrategy_ = function(wordWrap) {
   var newStrategy = wordWrap ? new cvox.WrappingPanStrategy() :
       new cvox.FixedPanStrategy();
   newStrategy.setDisplaySize(this.displayState_.textCellCount || 0);
   newStrategy.setContent(this.translatedContent_,
                          this.panStrategy_.viewPort.start);
   this.panStrategy_ = newStrategy;
   this.refresh_();
 };