Cleanup: Remove more forward declarations in various chrome/browser directories.

chrome/browser/browser_about_handler.h

 // Copyright (c) 2011 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.
 
 // Contains code for handling "about:" URLs in the browser process.
 
 #ifndef CHROME_BROWSER_BROWSER_ABOUT_HANDLER_H_
 #define CHROME_BROWSER_BROWSER_ABOUT_HANDLER_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/process.h"
 #include "base/stringprintf.h"
 #include "build/build_config.h"  // USE_TCMALLOC
 
 template <typename T> struct DefaultSingletonTraits;
 class GURL;
-class Profile;
 
 namespace content {
 class BrowserContext;
 }
 
 // Register a data source for a known source name. Safe to call multiple times.
 // |name| may be an unkown host (e.g. "chrome://foo/"); only handle known hosts.
 // In general case WillHandleBrowserAboutURL will initialize all data sources.
 // But in some case like navigating to chrome://oobe on boot and loading
 // chrome://terms in an iframe there, kChromeUITermsHost data source needs to
@@ skipping 53 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(AboutTcmallocOutputs);
 };
 
 // Glue between the callback task and the method in the singleton.
 void AboutTcmallocRendererCallback(base::ProcessId pid,
                                    const std::string& output);
 #endif
 
 #endif  // CHROME_BROWSER_BROWSER_ABOUT_HANDLER_H_