cc: Move UnoccludedContentRect to Occlusion.

cc/trees/occlusion.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 CC_TREES_OCCLUSION_H_
 #define CC_TREES_OCCLUSION_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/simple_enclosed_region.h"
+#include "ui/gfx/rect.h"
 #include "ui/gfx/transform.h"
 
-namespace gfx {
-class Rect;
-}  // namespace gfx
-
 namespace cc {
 
 class CC_EXPORT Occlusion {
  public:
   Occlusion();
   Occlusion(const gfx::Transform& draw_transform,
             const SimpleEnclosedRegion& occlusion_from_outside_target,
             const SimpleEnclosedRegion& occlusion_from_inside_target);
 
   bool IsOccluded(const gfx::Rect& content_rect) const;
+  gfx::Rect GetUnoccludedContentRect(const gfx::Rect& content_rect) const;
 
  private:
+  gfx::Rect GetUnoccludedRectInTargetSurface(
+      const gfx::Rect& content_rect) const;
+
   gfx::Transform draw_transform_;
   SimpleEnclosedRegion occlusion_from_outside_target_;
   SimpleEnclosedRegion occlusion_from_inside_target_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_OCCLUSION_H_