chrome: Cleanup class/struct forward declarations

chrome/browser/extensions/proxy_overridden_bubble_delegate.h

 // Copyright 2014 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_PROXY_OVERRIDDEN_BUBBLE_DELEGATE_H_
 #define CHROME_BROWSER_EXTENSIONS_PROXY_OVERRIDDEN_BUBBLE_DELEGATE_H_
 
 #include <stddef.h>
 
 #include <string>
 
 #include "base/macros.h"
 #include "chrome/browser/extensions/extension_message_bubble_controller.h"
 
-class Browser;
-
 namespace extensions {
 
 class ProxyOverriddenBubbleDelegate
     : public ExtensionMessageBubbleController::Delegate {
  public:
   explicit ProxyOverriddenBubbleDelegate(Profile* profile);
   ~ProxyOverriddenBubbleDelegate() override;
 
   // ExtensionMessageBubbleController::Delegate methods.
   bool ShouldIncludeExtension(const Extension* extension) override;
@@ skipping 21 matching lines @@
  private:
   // The ID of the extension we are showing the bubble for.
   std::string extension_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyOverriddenBubbleDelegate);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_PROXY_OVERRIDDEN_BUBBLE_DELEGATE_H_