Add tests to make sure copy/paste in an about:blank iframe in a hosted app works.

chrome/test/data/extensions/api_test/clipboard/extension/test.js

 // Copyright (c) 2011 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.
 
 // Clipboard permission test for Chrome.
 // browser_tests.exe --gtest_filter=ClipboardApiTest.Extension
 
 chrome.test.runTests([
   function domCopy() {
     if (document.execCommand('copy'))
       chrome.test.succeed();
     else
       chrome.test.fail('execCommand("copy") failed');
   },
   function domPaste() {
     if (document.execCommand('paste'))
       chrome.test.succeed();
     else
       chrome.test.fail('execCommand("paste") failed');
+  },
+  function copyInIframe() {
+    var ifr = document.createElement('iframe');
+    document.body.appendChild(ifr);
+    if (ifr.contentDocument.execCommand('copy'))
+      chrome.test.succeed();
+    else
+      chrome.test.fail('execCommand("copy") failed in iframe');
+  },
+  function pasteInIframe() {
+    var ifr = document.createElement('iframe');
+    document.body.appendChild(ifr);
+    if (ifr.contentDocument.execCommand('paste'))
+      chrome.test.succeed();
+    else
+      chrome.test.fail('execCommand("paste") failed in iframe');

[not at google - send to devlin, 2014/08/21 20:28:11]

Another line-saver: I don't know why we don't do:

chrome.test.assertEq(true, execCommand(..));

for all of these, rather than those 4 lines.

[Marijn Kruisselbrink, 2014/08/21 20:50:20]

You'd still need chrome.test.succeed() or fail() to cause test.runTests() to
actually go on with the next test. Although always calling succeed after an
assert will still have the desired overall effect, but with confusing output if
the test actually fails.

   }
 ]);