cc: Add testing stubs for proxy test

cc/trees/single_thread_proxy.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_TREES_SINGLE_THREAD_PROXY_H_
 #define CC_TREES_SINGLE_THREAD_PROXY_H_
 
 #include <limits>
 
 #include "base/time/time.h"
 #include "cc/animation/animation_events.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/trees/layer_tree_host_impl.h"
 #include "cc/trees/proxy.h"
 
 namespace cc {
 
 class ContextProvider;
 class LayerTreeHost;
 class LayerTreeHostSingleThreadClient;
 
-class SingleThreadProxy : public Proxy, LayerTreeHostImplClient {
+class CC_EXPORT SingleThreadProxy : public Proxy, LayerTreeHostImplClient {
  public:
   static scoped_ptr<Proxy> Create(
       LayerTreeHost* layer_tree_host,
       LayerTreeHostSingleThreadClient* client);
   virtual ~SingleThreadProxy();
 
   // Proxy implementation
   virtual bool CompositeAndReadback(void* pixels,
                                     const gfx::Rect& rect) OVERRIDE;
   virtual void FinishAllRendering() OVERRIDE;
@@ skipping 147 matching lines @@
  private:
   DebugScopedSetImplThread impl_thread_;
   DebugScopedSetMainThreadBlocked main_thread_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugScopedSetImplThreadAndMainThreadBlocked);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_SINGLE_THREAD_PROXY_H_