Make ChromeVox Next swallow key events that correspond to commands.

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

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
index 05b2009312576a97e48bd8d84413efacd2c26fbd..acc665d5faa6501bf0fa746c7b5047d31823d4f0 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
@@ -119,8 +119,7 @@ Background = function() {
 
   cvox.ExtensionBridge.addMessageListener(this.onMessage_);
 
-  document.addEventListener(
-      'keydown', cvox.ChromeVoxKbHandler.basicKeyDownActionsListener, true);
+  document.addEventListener('keydown', this.onKeyDown.bind(this), true);
   cvox.ChromeVoxKbHandler.commandHandler = this.onGotCommand.bind(this);
 
   // Classic keymap.
@@ -413,6 +412,19 @@ Background.prototype = {
   },
 
   /**
+   * Handles key down events.
+   *

[David Tseng, 2015/11/17 20:42:00]

nit: extra line

[dmazzoni, 2015/11/18 16:59:16]

Done.

+   * @param {Event} evt The key down event to process.
+   * @return {boolean} True if the default action should be performed.
+   */
+  onKeyDown: function(evt) {
+    if (!cvox.ChromeVoxKbHandler.basicKeyDownActionsListener(evt)) {
+      evt.preventDefault();
+      evt.stopPropagation();
+    }
+  },
+
+  /**
    * Open the options page in a new tab.
    */
   showOptionsPage: function() {