Attempt 2 at : Makes tests either use mock compositor or mock

ui/gfx/compositor/compositor_cc.h

 // Copyright (c) 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 UI_GFX_COMPOSITOR_COMPOSITOR_CC_H_
 #define UI_GFX_COMPOSITOR_COMPOSITOR_CC_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
@@ skipping 72 matching lines @@
       NON_EXPORTED_BASE(public WebKit::WebLayerClient) {
  public:
   CompositorCC(CompositorDelegate* delegate,
                gfx::AcceleratedWidget widget,
                const gfx::Size& size);
   virtual ~CompositorCC();
 
   static void Initialize(bool useThread);
   static void Terminate();
 
-  // If necessary enables the test context. If the test context is enabled the
-  // compositor does not render anything to screen.
-  static void EnableTestContextIfNecessary();
-
  protected:
   // Compositor implementation.
   virtual Texture* CreateTexture() OVERRIDE;
   virtual void Blur(const gfx::Rect& bounds) OVERRIDE;
   virtual void ScheduleDraw() OVERRIDE;
   virtual void OnNotifyStart(bool clear) OVERRIDE;
   virtual void OnNotifyEnd() OVERRIDE;
   virtual void OnWidgetSizeChanged() OVERRIDE;
   virtual void OnRootLayerChanged() OVERRIDE;
   virtual void DrawTree() OVERRIDE;
   virtual bool ReadPixels(SkBitmap* bitmap, const gfx::Rect& bounds) OVERRIDE;
 
   // WebLayerTreeViewClient implementation.
   virtual void animateAndLayout(double frameBeginTime);
   virtual void applyScrollAndScale(const WebKit::WebSize& scrollDelta,
                                    float scaleFactor);
   virtual void applyScrollDelta(const WebKit::WebSize&);
   virtual WebKit::WebGraphicsContext3D* createContext3D();
   virtual void didRebindGraphicsContext(bool success);
   virtual void scheduleComposite();
 
   // WebLayerClient implementation.
   virtual void notifyNeedsComposite();
 
  private:
   gfx::AcceleratedWidget widget_;
   WebKit::WebLayer root_web_layer_;
   WebKit::WebLayerTreeView host_;
 
-  // See description above SetTestContextEnabled.
-  static bool test_context_enabled_;
-
   DISALLOW_COPY_AND_ASSIGN(CompositorCC);
 };
 
 }  // namespace ui
 
 #endif  // UI_GFX_COMPOSITOR_COMPOSITOR_CC_H_