Fix keyboard/learn mode within login or locked screens

Bug: 796655
Change-Id: I8e1c8734c3cbfab3fbe3c9eb605662ea82bfeae1
Reviewed-on: https://chromium-review.googlesource.com/c/1287257
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Katie Dektar <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600828}

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

@@ -44,21 +44,6 @@ cvox.KbExplorer.init = function() {
   backgroundWindow['BrailleCommandHandler']['setEnabled'](false);
   backgroundWindow['GestureCommandHandler']['setEnabled'](false);
 
-  window.onbeforeunload = function(evt) {
-    backgroundWindow.removeEventListener(
-        'keydown', cvox.KbExplorer.onKeyDown, true);
-    backgroundWindow.removeEventListener(
-        'keyup', cvox.KbExplorer.onKeyUp, true);
-    backgroundWindow.removeEventListener(
-        'keypress', cvox.KbExplorer.onKeyPress, true);
-    chrome.brailleDisplayPrivate.onKeyEvent.removeListener(
-        cvox.KbExplorer.onBrailleKeyEvent);
-    chrome.accessibilityPrivate.onAccessibilityGesture.removeListener(
-        cvox.KbExplorer.onAccessibilityGesture);
-    chrome.accessibilityPrivate.setKeyboardListener(true, false);
-    backgroundWindow['BrailleCommandHandler']['setEnabled'](true);
-    backgroundWindow['GestureCommandHandler']['setEnabled'](true);
-  };
   if (localStorage['useClassic'] != 'true') {
     cvox.ChromeVoxKbHandler.handlerKeyMap = cvox.KeyMap.fromNext();
     cvox.ChromeVox.modKeyStr = 'Search';
@@ -87,8 +72,10 @@ cvox.KbExplorer.onKeyDown = function(evt) {
       cvox.KeyUtil.getReadableNameForKeyCode(evt.keyCode), false,
       cvox.AbstractTts.PERSONALITY_ANNOTATION);
 
-  // Allow Ctrl+W to be handled.
-  if (evt.keyCode == 87 && evt.ctrlKey) {
+  // Allow Ctrl+W or escape to be handled.
+  if ((evt.key == 'w' && evt.ctrlKey) || evt.key == 'Escape') {
+    cvox.KbExplorer.resetListeners_();
+    window.close();
     return true;
   }
 
@@ -248,3 +235,20 @@ cvox.KbExplorer.clearRange = function() {
   chrome.extension.getBackgroundPage()['ChromeVoxState']['instance']
                                       ['setCurrentRange'](null);
 };
+
+/** @private */
+cvox.KbExplorer.resetListeners_ = function() {
+  var backgroundWindow = chrome.extension.getBackgroundPage();
+  backgroundWindow.removeEventListener(
+      'keydown', cvox.KbExplorer.onKeyDown, true);
+  backgroundWindow.removeEventListener('keyup', cvox.KbExplorer.onKeyUp, true);
+  backgroundWindow.removeEventListener(
+      'keypress', cvox.KbExplorer.onKeyPress, true);
+  chrome.brailleDisplayPrivate.onKeyEvent.removeListener(
+      cvox.KbExplorer.onBrailleKeyEvent);
+  chrome.accessibilityPrivate.onAccessibilityGesture.removeListener(
+      cvox.KbExplorer.onAccessibilityGesture);
+  chrome.accessibilityPrivate.setKeyboardListener(true, false);
+  backgroundWindow['BrailleCommandHandler']['setEnabled'](true);
+  backgroundWindow['GestureCommandHandler']['setEnabled'](true);
+};