Added check to prevent extensions from injecting scrips into other extensions

chrome/browser/extensions/content_script_apitest.cc

 // 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.
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/api/permissions/permissions_api.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_tabstrip.h"
@@ skipping 65 matching lines @@
   ui_test_utils::GetCurrentTabTitle(browser(), &title);
   EXPECT_EQ(std::string("PASS"), UTF16ToUTF8(title));
 }
 
 // crbug.com/39249 -- content scripts js should not run on view source.
 IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentScriptViewSource) {
   ASSERT_TRUE(StartTestServer());
   ASSERT_TRUE(RunExtensionTest("content_scripts/view_source")) << message_;
 }
 
+// crbug.com/126257 -- content scripts should not get injected into other
+// extensions.
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentScriptOtherExtensions) {
+  host_resolver()->AddRule("a.com", "127.0.0.1");
+  ASSERT_TRUE(StartTestServer());
+  // First, load extension that sets up content script.
+  ASSERT_TRUE(RunExtensionTest("content_scripts/other_extensions/injector"))
+      << message_;
+  // Then load targeted extension to make sure its content isn't changed.
+  ASSERT_TRUE(RunExtensionTest("content_scripts/other_extensions/victim"))
+      << message_;
+}
+
 // crbug.com/120762
 IN_PROC_BROWSER_TEST_F(
     ExtensionApiTest,
     DISABLED_ContentScriptStylesInjectedIntoExistingRenderers) {
   ASSERT_TRUE(StartTestServer());
 
   content::WindowedNotificationObserver signal(
       chrome::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(browser()->profile()));
 
@@ skipping 46 matching lines @@
   EXPECT_TRUE(catcher.GetNextResult());
 }
 
 IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentScriptPermissionsApi) {
   RequestPermissionsFunction::SetIgnoreUserGestureForTests(true);
   RequestPermissionsFunction::SetAutoConfirmForTests(true);
   host_resolver()->AddRule("*.com", "127.0.0.1");
   ASSERT_TRUE(StartTestServer());
   ASSERT_TRUE(RunExtensionTest("content_scripts/permissions")) << message_;
 }