Enable all ESC-Fullscreen tests (Chrome Apps) for all platforms.

chrome/test/data/extensions/platform_apps/prevent_leave_fullscreen/main.js

 // Copyright 2013 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.
 
 chrome.app.runtime.onLaunched.addListener(function() {
   chrome.app.window.create('main.html', {}, function(win) {
     // The following key events handler will prevent the default behavior for
     // the ESC key, thus will prevent the ESC key to leave fullscreen.
     win.contentWindow.document.addEventListener('keydown', function(e) {
       e.preventDefault();
     });
     win.contentWindow.document.addEventListener('keyup', function(e) {
       e.preventDefault();
     });
 
     chrome.test.sendMessage('Launched', function(reply) {
       var doc = win.contentWindow.document;
+      doc.addEventListener('keydown', function(e) {
+        if (e.keyCode != 90) // 'z'
+          return;
+        chrome.test.sendMessage('KeyReceived');
+      });
 
       switch (reply) {
         case 'window':
           doc.addEventListener('keydown', function(e) {
             if (e.keyCode != 66) // 'b'
               return;
             doc.removeEventListener('keydown', arguments.callee);
             // We do one trip to the event loop to increase the chances that
             // fullscreen could have been left before the message is received.
             setTimeout(function() {
@@ skipping 18 matching lines @@
               });
             });
 
             doc.body.webkitRequestFullscreen();
           });
           break;
       }
     });
   });
 });