chrome: Cleanup class/struct forward declarations

chrome/browser/extensions/api/dashboard_private/dashboard_private_api.h

 // Copyright 2015 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_EXTENSIONS_API_DASHBOARD_PRIVATE_DASHBOARD_PRIVATE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DASHBOARD_PRIVATE_DASHBOARD_PRIVATE_API_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "chrome/browser/bitmap_fetcher/bitmap_fetcher_delegate.h"
 #include "chrome/browser/extensions/chrome_extension_function_details.h"
 #include "chrome/browser/extensions/extension_install_prompt.h"
 #include "chrome/browser/extensions/webstore_install_helper.h"
 #include "chrome/common/extensions/api/dashboard_private.h"
 #include "extensions/browser/extension_function.h"
 
-class GURL;
 class SkBitmap;
 
-namespace chrome {
-class BitmapFetcher;
-}  // namespace chrome
-
 namespace extensions {
 
 class Extension;
 
 class DashboardPrivateShowPermissionPromptForDelegatedInstallFunction
     : public UIThreadExtensionFunction,
       public WebstoreInstallHelper::Delegate {
  public:
   DECLARE_EXTENSION_FUNCTION(
       "dashboardPrivate.showPermissionPromptForDelegatedInstall",
@@ skipping 37 matching lines @@
   std::unique_ptr<ExtensionInstallPrompt> install_prompt_;
 
   DISALLOW_COPY_AND_ASSIGN(
       DashboardPrivateShowPermissionPromptForDelegatedInstallFunction);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DASHBOARD_PRIVATE_DASHBOARD_PRIVATE_API_H_