Do not clip inside OcclusionTracker.

cc/trees/occlusion_tracker.h

Index: cc/trees/occlusion_tracker.h
diff --git a/cc/trees/occlusion_tracker.h b/cc/trees/occlusion_tracker.h
index 132b3fa3160c8430d3dc2dbdb789d3d8f66206f1..8e4be077a50393a4b2d68e24e5d380142c3decc6 100644
--- a/cc/trees/occlusion_tracker.h
+++ b/cc/trees/occlusion_tracker.h
@@ -32,8 +32,7 @@ class RenderSurface;
 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
@@ -48,28 +47,22 @@ class CC_EXPORT OcclusionTrackerBase {
   // 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, 2013/09/10 14:36:37]

and |impl_draw_transform_is_known|

   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, 2013/09/10 14:36:37]

and |impl_draw_t_i_known|

   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
@@ -87,9 +80,9 @@ class CC_EXPORT OcclusionTrackerBase {
   }
 
   // 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);
   }
 
@@ -152,7 +145,6 @@ class CC_EXPORT OcclusionTrackerBase {
   // 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_;