Added check to prevent extensions from injecting scrips into other extensions

chrome/test/data/extensions/api_test/content_scripts/other_extensions/injector/inject.js

Index: chrome/test/data/extensions/api_test/content_scripts/other_extensions/injector/inject.js
diff --git a/chrome/test/data/extensions/api_test/content_scripts/other_extensions/injector/inject.js b/chrome/test/data/extensions/api_test/content_scripts/other_extensions/injector/inject.js
new file mode 100644
index 0000000000000000000000000000000000000000..77f4c366041fb5e1eed8b78caabae1b37e3aa664
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/content_scripts/other_extensions/injector/inject.js
@@ -0,0 +1,13 @@
+// Copyright (c) 2012 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.
+
+console.log('INJECTOR: Injecting content script!');
+
+var content = document.getElementById('content');
+if (content) {
+  content.innerText = 'Injected!!!';
+  console.log('INJECTOR: Changed content to: ' + content.innerText);
+} else {
+  console.log('INJECTOR: Cannot find content!?');
+}