cc: Clean up LayerTreeTest and TestHooks.

cc/test/layer_tree_test.h

Index: cc/test/layer_tree_test.h
diff --git a/cc/test/layer_tree_test.h b/cc/test/layer_tree_test.h
index 140cc7927bf9135796c0aa718f94d5d31738546f..ec52939716e8f51c64ba8d0cb620b78554114c54 100644
--- a/cc/test/layer_tree_test.h
+++ b/cc/test/layer_tree_test.h
@@ -8,8 +8,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/threading/thread.h"
 #include "cc/animation/animation_delegate.h"
-#include "cc/test/proxy_impl_for_test.h"
-#include "cc/test/proxy_main_for_test.h"
 #include "cc/test/remote_proto_channel_bridge.h"
 #include "cc/test/test_hooks.h"
 #include "cc/trees/layer_tree_host.h"
@@ -26,6 +24,8 @@ class LayerTreeHost;
 class LayerTreeHostForTesting;
 class LayerTreeHostClient;
 class LayerTreeHostImpl;
+class ProxyImpl;
+class ProxyMain;
 class RemoteChannelImplForTest;
 class TestContextProvider;
 class TestGpuMemoryBufferManager;
@@ -156,14 +156,7 @@ class LayerTreeTest : public testing::Test, public TestHooks {
   }
 
   // Use these only for tests in threaded or remote mode.
-  ProxyMainForTest* GetProxyMainForTest() const;
-  ProxyImplForTest* GetProxyImplForTest() const;
-
-  // Use this only for tests in threaded mode.
-  ThreadedChannelForTest* GetThreadedChannelForTest() const;
-
-  // Use this only for tests in remote mode.
-  RemoteChannelImplForTest* GetRemoteChannelImplForTest() const;
+  ProxyMain* GetProxyMain() const;
 
   void DestroyLayerTreeHost();
   void DestroyRemoteClientHost() override;