content: Cleanup class/struct forward declarations

content/renderer/mojo_bindings_controller.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 CONTENT_RENDERER_MOJO_BINDINGS_CONTROLLER_H_
 #define CONTENT_RENDERER_MOJO_BINDINGS_CONTROLLER_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "content/public/renderer/render_frame_observer_tracker.h"
 #include "mojo/public/cpp/system/core.h"
 
-namespace gin {
-class PerContextData;
-}
-
 namespace content {
 
 class MojoContextState;
 
 enum class MojoBindingsType { FOR_WEB_UI, FOR_LAYOUT_TESTS, FOR_HEADLESS };
 
 // MojoBindingsController is responsible for enabling the renderer side of mojo
 // bindings. It creates (and destroys) a MojoContextState at the appropriate
 // times and handles the necessary browser messages. MojoBindingsController
 // destroys itself when the RendererFrame it is created with is destroyed.
@@ skipping 20 matching lines @@
   void OnDestruct() override;
 
   const MojoBindingsType bindings_type_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoBindingsController);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MOJO_BINDINGS_CONTROLLER_H_