Mac Overlays: Add sandwich strategy

cc/output/overlay_strategy_common.h

Index: cc/output/overlay_strategy_common.h
diff --git a/cc/output/overlay_strategy_common.h b/cc/output/overlay_strategy_common.h
index 0291be7c4272f84e4ca021af331a307b7394fa5c..6d8c40559eb6afed356c8430ec9d0c73040fb75b 100644
--- a/cc/output/overlay_strategy_common.h
+++ b/cc/output/overlay_strategy_common.h
@@ -16,22 +16,35 @@ class OverlayCandidateValidator;
 class StreamVideoDrawQuad;
 class TextureDrawQuad;
 
+class CC_EXPORT OverlayStrategyCommonDelegate {
+ public:
+  virtual ~OverlayStrategyCommonDelegate() {}
+  virtual bool TryOverlay(OverlayCandidateValidator* capability_checker,
+                          RenderPassList* render_passes_in_draw_order,
+                          OverlayCandidateList* candidate_list,
+                          const OverlayCandidate& candidate,
+                          QuadList::Iterator iter,
+                          float device_scale_factor) = 0;
+};
+
 class CC_EXPORT OverlayStrategyCommon : public OverlayProcessor::Strategy {
  public:
-  explicit OverlayStrategyCommon(OverlayCandidateValidator* capability_checker);
+  explicit OverlayStrategyCommon(OverlayCandidateValidator* capability_checker,
+                                 OverlayStrategyCommonDelegate* delegate);
   ~OverlayStrategyCommon() override;
 
   bool Attempt(RenderPassList* render_passes_in_draw_order,
-               OverlayCandidateList* candidate_list) override;
+               OverlayCandidateList* candidate_list,
+               float device_scale_factor) override;
+
+  // Returns true if |draw_quad| will not block quads underneath from becoming
+  // an overlay.
+  static bool IsInvisibleQuad(const DrawQuad* draw_quad);
 
  protected:
   bool GetCandidateQuadInfo(const DrawQuad& draw_quad,
                             OverlayCandidate* quad_info);
 
-  // Returns true if |draw_quad| will not block quads underneath from becoming
-  // an overlay.
-  bool IsInvisibleQuad(const DrawQuad* draw_quad);
-
   // Returns true if |draw_quad| is of a known quad type and contains an
   // overlayable resource.
   bool IsOverlayQuad(const DrawQuad* draw_quad);
@@ -43,14 +56,9 @@ class CC_EXPORT OverlayStrategyCommon : public OverlayProcessor::Strategy {
   bool GetIOSurfaceQuadInfo(const IOSurfaceDrawQuad& quad,
                             OverlayCandidate* quad_info);
 
-  virtual bool TryOverlay(OverlayCandidateValidator* capability_checker,
-                          RenderPassList* render_passes_in_draw_order,
-                          OverlayCandidateList* candidate_list,
-                          const OverlayCandidate& candidate,
-                          QuadList::Iterator iter) = 0;
-
  private:
   OverlayCandidateValidator* capability_checker_;
+  scoped_ptr<OverlayStrategyCommonDelegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(OverlayStrategyCommon);
 };