blink: Cleanup class forward declarations

third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.h

 // Copyright 2013 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 WebLayerTreeViewImplForTesting_h
 #define WebLayerTreeViewImplForTesting_h
 
 #include "cc/test/test_task_graph_runner.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "public/platform/WebLayerTreeView.h"
 #include <memory>
 
 namespace cc {
 class LayerTreeHost;
 class LayerTreeSettings;
 }
 
 namespace blink {
 
-class WebCompositorAnimationTimeline;
 class WebLayer;
 
 // Dummy WeblayerTeeView that does not support any actual compositing.
 class WebLayerTreeViewImplForTesting
     : public blink::WebLayerTreeView,
       public cc::LayerTreeHostClient,
       public cc::LayerTreeHostSingleThreadClient {
   WTF_MAKE_NONCOPYABLE(WebLayerTreeViewImplForTesting);
 
  public:
@@ skipping 69 matching lines @@
   void DidLoseCompositorFrameSink() override {}
 
  private:
   cc::TestTaskGraphRunner m_taskGraphRunner;
   std::unique_ptr<cc::LayerTreeHost> m_layerTreeHost;
 };
 
 }  // namespace blink
 
 #endif  // WebLayerTreeViewImplForTesting_h