Do not clip inside OcclusionTracker.

cc/trees/occlusion_tracker.h

 // Copyright 2012 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_TRACKER_H_
 #define CC_TREES_OCCLUSION_TRACKER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 14 matching lines @@
 // class is called to notify it about the current target surface. Then,
 // occlusion in the content space of the current layer may be queried, via
 // methods such as Occluded() and UnoccludedContentRect(). If the current layer
 // owns a RenderSurfaceImpl, then occlusion on that RenderSurfaceImpl may also
 // be queried via surfaceOccluded() and surfaceUnoccludedContentRect(). Finally,
 // once finished with the layer, occlusion behind the layer should be marked by
 // calling MarkOccludedBehindLayer().
 template <typename LayerType, typename RenderSurfaceType>
 class CC_EXPORT OcclusionTrackerBase {
  public:
-  OcclusionTrackerBase(gfx::Rect screen_space_clip_rect,
-                       bool record_metrics_for_frame);
+  explicit OcclusionTrackerBase(bool record_metrics_for_frame);
   ~OcclusionTrackerBase();
 
   // Called at the beginning of each step in the LayerIterator's front-to-back
   // traversal. If |prevent_occlusion| is true, the layer will be considered
   // unoccluded.
   void EnterLayer(const LayerIteratorPosition<LayerType>& layer_iterator,
                   bool prevent_occlusion);
   // Called at the end of each step in the LayerIterator's front-to-back
   // traversal.
   void LeaveLayer(const LayerIteratorPosition<LayerType>& layer_iterator);
 
   // Returns true if the given rect in content space for a layer is fully
   // occluded in either screen space or the layer's target surface.
   // |render_target| is the contributing layer's render target, and
-  // |draw_transform|, |transformsToTargetKnown| and |clippedRectInTarget| are
-  // relative to that.
+  // |draw_transform| is relative to that.

[danakj, 2013/09/16 17:29:08]

draw_transform and impl_draw_transform_is_unknown are relative to that.

[alokp, 2013/09/17 00:31:41]

Done.

   bool Occluded(const LayerType* render_target,
                 gfx::Rect content_rect,
                 const gfx::Transform& draw_transform,
                 bool impl_draw_transform_is_unknown,
-                bool is_clipped,
-                gfx::Rect clip_rect_in_target,
                 bool* has_occlusion_from_outside_target_surface) const;
 
   // Gives an unoccluded sub-rect of |content_rect| in the content space of a
   // layer. Used when considering occlusion for a layer that paints/draws
   // something. |render_target| is the contributing layer's render target, and
-  // |draw_transform|, |transformsToTargetKnown| and |clippedRectInTarget| are
-  // relative to that.
+  // |draw_transform| is relative to that.

[danakj, 2013/09/16 17:29:08]

draw_transform and impl_draw_transform_is_unknown are relative to that.

[alokp, 2013/09/17 00:31:41]

Done.

   gfx::Rect UnoccludedContentRect(
       const LayerType* render_target,
       gfx::Rect content_rect,
       const gfx::Transform& draw_transform,
       bool impl_draw_transform_is_unknown,
-      bool is_clipped,
-      gfx::Rect clip_rect_in_target,
       bool* has_occlusion_from_outside_target_surface) const;
 
   // Gives an unoccluded sub-rect of |content_rect| in the content space of the
   // render_target owned by the layer. Used when considering occlusion for a
   // contributing surface that is rendering into another target.
   gfx::Rect UnoccludedContributingSurfaceContentRect(
       const LayerType* layer,
       bool for_replica,
       gfx::Rect content_rect,
       bool* has_occlusion_from_outside_target_surface) const;
 
   // Report operations for recording overdraw metrics.
   OverdrawMetrics* overdraw_metrics() const {
     return overdraw_metrics_.get();
   }
 
   // Gives the region of the screen that is not occluded by something opaque.
-  Region ComputeVisibleRegionInScreen() const {
+  Region ComputeVisibleRegionInScreen(gfx::Rect screen_space_clip_rect) const {
     DCHECK(!stack_.back().target->parent());
-    return SubtractRegions(screen_space_clip_rect_,
+    return SubtractRegions(screen_space_clip_rect,
                            stack_.back().occlusion_from_inside_target);
   }
 
   void set_minimum_tracking_size(gfx::Size size) {
     minimum_tracking_size_ = size;
   }
 
   // The following is used for visualization purposes.
   void set_occluding_screen_space_rects_container(
       std::vector<gfx::Rect>* rects) {
@@ skipping 42 matching lines @@
 
   // Called when visiting a layer representing a contributing surface. This
   // indicates that we are leaving our current surface, and entering the new
   // one. We then perform any operations required for merging results from the
   // child subtree into its parent.
   void LeaveToRenderTarget(const LayerType* new_target);
 
   // Add the layer's occlusion to the tracked state.
   void MarkOccludedBehindLayer(const LayerType* layer);
 
-  gfx::Rect screen_space_clip_rect_;
   scoped_ptr<class OverdrawMetrics> overdraw_metrics_;
   gfx::Size minimum_tracking_size_;
   bool prevent_occlusion_;
 
   // This is used for visualizing the occlusion tracking process.
   std::vector<gfx::Rect>* occluding_screen_space_rects_;
   std::vector<gfx::Rect>* non_occluding_screen_space_rects_;
 
   DISALLOW_COPY_AND_ASSIGN(OcclusionTrackerBase);
 };
 
 typedef OcclusionTrackerBase<Layer, RenderSurface> OcclusionTracker;
 typedef OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl> OcclusionTrackerImpl;
 #if !defined(COMPILER_MSVC)
 extern template class OcclusionTrackerBase<Layer, RenderSurface>;
 extern template class OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl>;
 #endif
 
 }  // namespace cc
 
 #endif  // CC_TREES_OCCLUSION_TRACKER_H_