ui: Cleanup class/struct forward declarations

ui/android/resources/resource_manager.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 UI_ANDROID_RESOURCES_RESOURCE_MANAGER_H_
 #define UI_ANDROID_RESOURCES_RESOURCE_MANAGER_H_
 
 #include <memory>
 #include <unordered_map>
 #include <unordered_set>
 
 #include "base/android/jni_android.h"
 #include "cc/resources/scoped_ui_resource.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/android/resources/crushed_sprite_resource.h"
 #include "ui/android/ui_android_export.h"
 #include "ui/gfx/geometry/insets_f.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace ui {
 
-class UIResourceProvider;
-
 // A Java counterpart will be generated for this enum.
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.ui.resources
 enum AndroidResourceType {
   ANDROID_RESOURCE_TYPE_STATIC = 0,
   ANDROID_RESOURCE_TYPE_DYNAMIC,
   ANDROID_RESOURCE_TYPE_DYNAMIC_BITMAP,
   ANDROID_RESOURCE_TYPE_SYSTEM,
   ANDROID_RESOURCE_TYPE_CRUSHED_SPRITE,
 
   ANDROID_RESOURCE_TYPE_COUNT,
@@ skipping 56 matching lines @@
     return resource && resource->ui_resource ? resource->ui_resource->id() : 0;
   }
 
  protected:
   virtual ~ResourceManager() {}
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_RESOURCES_RESOURCE_MANAGER_H_