Implement auto read on load complete

This cl adds an option/preference for a user to trigger automatic read/continuous read on load. Defaults to off.

BUG=672938
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2577473003
Cr-Commit-Position: refs/heads/master@{#439110}

chrome/browser/resources/chromeos/chromevox/chromevox/background/options.html

@@ -34,6 +34,13 @@
     </label>
   </div>
 
+  <div class="option">
+    <input id="autoRead" type="checkbox" class="checkbox pref" name="autoRead"></input>
+    <label for="autoRead" class="i18n" msgid="options_auto_read">
+      Automatically read a page after it finishes loading.
+    </label>
+  </div>
+
   <h2 class="i18n" msgid="options_voices">Voices</h2>
   <p class="i18n description" msgid="options_voices_description" id="voices_description">
     Change the current voice by selecting an option from the list below.

chrome/browser/resources/chromeos/chromevox/chromevox/background/prefs.js

@@ -60,6 +60,7 @@ cvox.ChromeVoxPrefs = function() {
  */
 cvox.ChromeVoxPrefs.DEFAULT_PREFS = {
   'active': true,
+  'autoRead': false,
   'brailleCaptions': false,
   'brailleSideBySide': true,
   // TODO(dtseng): Leaking state about multiple key maps here until we have a

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

@@ -297,6 +297,15 @@ DesktopAutomationHandler.prototype = {
       // ChromeVox.
       this.createTextEditHandlerIfNeeded_(focus);
 
+      // If auto read is set, skip focus recovery and start reading from the top.
+      if (localStorage['autoRead'] == 'true' &&
+          AutomationUtil.getTopLevelRoot(evt.target) == evt.target) {
+        ChromeVoxState.instance.setCurrentRange(cursors.Range.fromNode(evt.target));
+        cvox.ChromeVox.tts.stop();
+        CommandHandler.onCommand('readFromHere');
+        return;
+      }
+
       // If initial focus was already placed on this page (e.g. if a user starts
       // tabbing before load complete), then don't move ChromeVox's position on
       // the page.

chrome/browser/resources/chromeos/chromevox/strings/chromevox_strings.grd

@@ -474,6 +474,9 @@
       <message desc="An option to use more verbose feedback for the user." name="IDS_CHROMEVOX_OPTIONS_VERBOSITY_VERBOSE">
         Enable verbose descriptions.
       </message>
+      <message desc="An option to automatically read the page after it loads." name="IDS_CHROMEVOX_OPTIONS_AUTO_READ">
+        Automatically read page after it finishes loading.
+      </message>
       <message desc="An option to show the cursor between characters." name="IDS_CHROMEVOX_OPTIONS_CURSOR_BETWEEN_CHARACTERS">
         Place cursor between characters when editing text (like Mac OS X).
       </message>