Implement chromium.self in content scripts, fix bugs

chrome/test/data/extensions/content_script_inject/script2.js

+// Copyright (c) 2009 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.
+
+// Tests that we cannot see global variables defined in other content scripts.
+// This var was defined in script1a.js. We run each content script in a separate
+// context, so we shouldn't see globals across them.
+function testCannotSeeOtherContentScriptGlobals() {
+  assert(typeof script1_var == "undefined");
+}
+
+runAllTests();