cc: Cleanup - remove unused 'Webkit' forward declaration.

cc/test/layer_tree_test.h

 // Copyright 2011 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 CC_TEST_LAYER_TREE_TEST_H_
 #define CC_TEST_LAYER_TREE_TEST_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/threading/thread.h"
 #include "cc/animation/animation_delegate.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_host_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace Webkit {
-class WebGraphicsContext3D;
-}
-
 namespace cc {
 class FakeExternalBeginFrameSource;
 class FakeLayerTreeHostClient;
 class FakeOutputSurface;
 class LayerImpl;
 class LayerTreeHost;
 class LayerTreeHostClient;
 class LayerTreeHostImpl;
 class TestContextProvider;
 class TestWebGraphicsContext3D;
@@ skipping 345 matching lines @@
   SINGLE_AND_MULTI_THREAD_DIRECT_RENDERER_TEST_F(TEST_FIXTURE_NAME); \
   SINGLE_AND_MULTI_THREAD_DELEGATING_RENDERER_TEST_F(TEST_FIXTURE_NAME)
 
 // Some tests want to control when notify ready for activation occurs,
 // but this is not supported in the single-threaded case.
 #define SINGLE_AND_MULTI_THREAD_BLOCKNOTIFY_TEST_F(TEST_FIXTURE_NAME) \
   SINGLE_THREAD_NOIMPL_TEST_F(TEST_FIXTURE_NAME);                     \
   MULTI_THREAD_TEST_F(TEST_FIXTURE_NAME)
 
 #endif  // CC_TEST_LAYER_TREE_TEST_H_