Attempt four at landing the "histogram.h removed from message_loop.h" patch.

chrome/browser/cancelable_request.h

 // Copyright (c) 2010 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.
 
 // CancelableRequestProviders and Consumers work together to make requests that
 // execute on a background thread in the provider and return data to the
 // consumer. These class collaborate to keep a list of open requests and to
 // make sure that requests to not outlive either of the objects involved in the
 // transaction.
 //
@@ skipping 78 matching lines @@
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/cancellation_flag.h"
 #include "base/lock.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
 #include "base/task.h"
 
 class CancelableRequestBase;
 class CancelableRequestConsumerBase;
 
 // CancelableRequestProvider --------------------------------------------------
 //
 // This class is threadsafe. Requests may be added or canceled from any thread,
 // but a task must only be canceled from the same thread it was initially run
 // on.
@@ skipping 448 matching lines @@
   }
 
   // The value.
   Type value;
 
  protected:
   virtual ~CancelableRequest1() {}
 };
 
 #endif  // CHROME_BROWSER_CANCELABLE_REQUEST_H__