Change these tests to actually trigger the execCommand from the iframe context.

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

Index: chrome/test/data/extensions/api_test/clipboard/extension_no_permission/test.js
diff --git a/chrome/test/data/extensions/api_test/clipboard/extension_no_permission/test.js b/chrome/test/data/extensions/api_test/clipboard/extension_no_permission/test.js
index 544c6ed2853333a27d38f2b87b3bb383ded76013..2264f07ad9e82e8df45a24334b758bd5c2dd88ac 100644
--- a/chrome/test/data/extensions/api_test/clipboard/extension_no_permission/test.js
+++ b/chrome/test/data/extensions/api_test/clipboard/extension_no_permission/test.js
@@ -21,17 +21,24 @@ chrome.test.runTests([
   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');
+    window.command = 'copy';
+    ifr.contentDocument.write('<script src="iframe.js"></script>');
   },
   function pasteInIframe() {
     var ifr = document.createElement('iframe');
     document.body.appendChild(ifr);
-    if (ifr.contentDocument.execCommand('paste'))
-      chrome.test.fail('execCommand("paste") succeeded in iframe');
-    else
-      chrome.test.succeed();
+    window.command = 'paste';
+    ifr.contentDocument.write('<script src="iframe.js"></script>');
   }
 ]);
+
+function testDone(result) {
+  // 'copy' should always succeed regardless of the clipboardWrite permission,
+  // for backwards compatibility. 'paste' should always fail because the
+  // extension doesn't have clipboardRead.
+  var expected = window.command === 'copy';
+  if (result === expected)
+    chrome.test.succeed();
+  else
+    chrome.test.fail();
+}