Use a direct include of strings headers in chrome_frame/.

chrome_frame/test/automation_client_mock.h

 // 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.
 
 #ifndef CHROME_FRAME_TEST_AUTOMATION_CLIENT_MOCK_H_
 #define CHROME_FRAME_TEST_AUTOMATION_CLIENT_MOCK_H_
 
 #include <windows.h>
 #include <string>
 
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "chrome_frame/chrome_frame_automation.h"
 #include "chrome_frame/test/chrome_frame_test_utils.h"
 #include "chrome_frame/test/proxy_factory_mock.h"
 #include "chrome_frame/utils.h"
 #include "gmock/gmock.h"
 
 using testing::StrictMock;
 
 // ChromeFrameAutomationClient [CFAC] tests.
 struct MockCFDelegate : public ChromeFrameDelegateImpl {
@@ skipping 157 matching lines @@
   virtual void SetUp() {
     dummy_sender_.ForwardTo(&mock_proxy_);
     tracker_.reset(new AutomationHandleTracker());
 
     client_ = new ChromeFrameAutomationClient;
     client_->set_proxy_factory(&factory_);
   }
 };
 
 #endif  // CHROME_FRAME_TEST_AUTOMATION_CLIENT_MOCK_H_