chrome: Cleanup class/struct forward declarations

chrome/browser/ui/webui/chromeos/slow_trace_ui.h

 // Copyright 2013 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_BROWSER_UI_WEBUI_CHROMEOS_SLOW_TRACE_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_SLOW_TRACE_UI_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/public/browser/url_data_source.h"
 #include "content/public/browser/web_ui_controller.h"
 #include "ui/base/layout.h"
 
 namespace base {
-class RefCountedMemory;
 class RefCountedString;
 }
 
 namespace chromeos {
 
 // This class provides the source for chrome://slow_trace/.  It needs to be a
 // separate handler that chrome://slow, because URLDataSource and
 // WebUIDataSource are not descended from each other, and WebUIDataSource
 // doesn't allow the MimeType to be dynamically specified.
 class SlowTraceSource : public content::URLDataSource {
@@ skipping 21 matching lines @@
  public:
   explicit SlowTraceController(content::WebUI* web_ui);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SlowTraceController);
 };
 
 } // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_SLOW_TRACE_UI_H_