Implement support for <audio> in ChromeVox Next.

chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js
index f19913fb28a39a92d5448ed93be4b16be93317c1..0b6ce577a9d1ec167f0e307249fcb958e40cb7d3 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js
@@ -162,6 +162,9 @@ Output.RULES = {
     alert: {
       speak: '!doNotInterrupt $role $descendants'
     },
+    button: {
+      speak: '$name $value $description $role',

[dmazzoni, 2015/04/24 13:41:08]

As suggested in the other CL, how about:

$name $description $help $value $ole

...and do this to all rules where we have $name now. Then when we have the new
name calc available we can just replace with $name only.

+    },
     checkBox: {
       speak: '$name $role $checked'
     },
@@ -207,7 +210,7 @@ Output.RULES = {
           '@describe_radio_unselected($name))'
     },
     slider: {
-      speak: '@describe_slider($value, $name)'
+      speak: '@describe_slider($value, $name) $help'
     },
     staticText: {
       speak: '$value $name'
@@ -303,13 +306,26 @@ Output.EventType = {
 Output.prototype = {
   /**
    * Gets the output buffer for speech.
+   * @param {string=} opt_separator Used to join components of the output.
    * @return {!cvox.Spannable}
    */
-  toSpannable: function() {
+  toSpannable: function(opt_separator) {
+    opt_separator = opt_separator || '';
     return this.buffer_.reduce(function(prev, cur) {
+      if (prev === null)
+        return cur;
+      prev.append(opt_separator);
       prev.append(cur);
       return prev;
-    }, new cvox.Spannable());
+    }, null);
+  },
+
+  /**
+   * Gets the output buffer for speech with separator '|'.
+   * @return {!cvox.Spannable}
+   */
+  toSpannableForTest: function() {
+    return this.toSpannable('|');
   },
 
   /**