Use refs for GraphicsContext

third_party/WebKit/Source/core/paint/ClipScope.h

 // Copyright 2014 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 ClipScope_h
 #define ClipScope_h
 
 #include "platform/graphics/GraphicsContext.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 class ClipScope {
     DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
     WTF_MAKE_NONCOPYABLE(ClipScope);
 public:
-    ClipScope(GraphicsContext* context)
+    ClipScope(GraphicsContext& context)
         : m_context(context)
         , m_clipCount(0) { }
     ~ClipScope();
 
     void clip(const LayoutRect& clipRect, SkRegion::Op operation);
 
 private:
-    GraphicsContext* m_context;
+    GraphicsContext& m_context;
     int m_clipCount;
 };
 
 } // namespace blink
 
 #endif // ClipScope_h