cc: Stop using drawableContentRect for occlusion.

cc/occlusion_tracker.cc

Index: cc/occlusion_tracker.cc
diff --git a/cc/occlusion_tracker.cc b/cc/occlusion_tracker.cc
index 7740fdabe5d13b570ece81ac70109b3bbbc55c35..cfd9acbe0c92aa13a0548dcd3f89cfbc70676301 100644
--- a/cc/occlusion_tracker.cc
+++ b/cc/occlusion_tracker.cc
@@ -47,6 +47,7 @@ void OcclusionTrackerBase<LayerType, RenderSurfaceType>::leaveLayer(const LayerI
 
     if (layerIterator.representsItself)
         markOccludedBehindLayer(layerIterator.currentLayer);
+    // TODO(danakj): This should be done when entering the contributing surface, but in a way that the surface's own occlusion won't occlude itself.
     else if (layerIterator.representsContributingRenderSurface)
         leaveToRenderTarget(renderTarget);
 }
@@ -279,15 +280,15 @@ void OcclusionTrackerBase<LayerType, RenderSurfaceType>::markOccludedBehindLayer
     if (layerIsInUnsorted3dRenderingContext(layer))
         return;
 
+    if (!layerTransformsToTargetKnown(layer))
+        return;
+
     Region opaqueContents = layer->visibleContentOpaqueRegion();
     if (opaqueContents.IsEmpty())
         return;
 
     DCHECK(layer->visibleContentRect().Contains(opaqueContents.bounds()));
 
-    if (!layerTransformsToTargetKnown(layer))
-        return;
-
     bool clipped;
     gfx::QuadF visibleTransformedQuad = MathUtil::mapQuad(layer->drawTransform(), gfx::QuadF(opaqueContents.bounds()), clipped);
     // FIXME: Find a rect interior to each transformed quad.
@@ -295,7 +296,7 @@ void OcclusionTrackerBase<LayerType, RenderSurfaceType>::markOccludedBehindLayer
         return;
 
     gfx::Rect clipRectInTarget = gfx::IntersectRects(
-        layerClipRectInTarget(layer),
+        layer->renderTarget()->renderSurface()->contentRect(),
         screenSpaceClipRectInTargetSurface(layer->renderTarget()->renderSurface(), m_screenSpaceClipRect));
 
     for (Region::Iterator opaqueContentRects(opaqueContents); opaqueContentRects.has_rect(); opaqueContentRects.next()) {
@@ -335,7 +336,7 @@ void OcclusionTrackerBase<LayerType, RenderSurfaceType>::markOccludedBehindLayer
 }
 
 template<typename LayerType, typename RenderSurfaceType>
-bool OcclusionTrackerBase<LayerType, RenderSurfaceType>::occluded(const LayerType* renderTarget, const gfx::Rect& contentRect, const gfx::Transform& drawTransform, bool implDrawTransformIsUnknown, const gfx::Rect& clippedRectInTarget, bool* hasOcclusionFromOutsideTargetSurface) const
+bool OcclusionTrackerBase<LayerType, RenderSurfaceType>::occluded(const LayerType* renderTarget, gfx::Rect contentRect, const gfx::Transform& drawTransform, bool implDrawTransformIsUnknown, bool isClipped, gfx::Rect clipRectInTarget, bool* hasOcclusionFromOutsideTargetSurface) const
 {
     if (hasOcclusionFromOutsideTargetSurface)
         *hasOcclusionFromOutsideTargetSurface = false;
@@ -363,13 +364,14 @@ bool OcclusionTrackerBase<LayerType, RenderSurfaceType>::occluded(const LayerTyp
     // Take the ToEnclosingRect at each step, as we want to contain any unoccluded partial pixels in the resulting Rect.
     Region unoccludedRegionInTargetSurface = gfx::ToEnclosingRect(MathUtil::mapClippedRect(drawTransform, gfx::RectF(contentRect)));
     // Layers can't clip across surfaces, so count this as internal occlusion.
-    // TODO(danakj): This would change if we clipped to the visibleContentRect().
-    unoccludedRegionInTargetSurface.Intersect(clippedRectInTarget);
+    if (isClipped)
+      unoccludedRegionInTargetSurface.Intersect(clipRectInTarget);
     unoccludedRegionInTargetSurface.Subtract(m_stack.back().occlusionFromInsideTarget);
     gfx::RectF unoccludedRectInTargetSurfaceWithoutOutsideOcclusion = unoccludedRegionInTargetSurface.bounds();
     unoccludedRegionInTargetSurface.Subtract(m_stack.back().occlusionFromOutsideTarget);
 
     // Treat other clipping as occlusion from outside the surface.
+    // TODO(danakj): Clip to visibleContentRect?
     unoccludedRegionInTargetSurface.Intersect(renderTarget->renderSurface()->contentRect());
     unoccludedRegionInTargetSurface.Intersect(screenSpaceClipRectInTargetSurface(renderTarget->renderSurface(), m_screenSpaceClipRect));
 
@@ -384,7 +386,7 @@ bool OcclusionTrackerBase<LayerType, RenderSurfaceType>::occluded(const LayerTyp
 }
 
 template<typename LayerType, typename RenderSurfaceType>
-gfx::Rect OcclusionTrackerBase<LayerType, RenderSurfaceType>::unoccludedContentRect(const LayerType* renderTarget, const gfx::Rect& contentRect, const gfx::Transform& drawTransform, bool implDrawTransformIsUnknown, const gfx::Rect& clippedRectInTarget, bool* hasOcclusionFromOutsideTargetSurface) const
+gfx::Rect OcclusionTrackerBase<LayerType, RenderSurfaceType>::unoccludedContentRect(const LayerType* renderTarget, gfx::Rect contentRect, const gfx::Transform& drawTransform, bool implDrawTransformIsUnknown, bool isClipped, gfx::Rect clipRectInTarget, bool* hasOcclusionFromOutsideTargetSurface) const
 {
     if (hasOcclusionFromOutsideTargetSurface)
         *hasOcclusionFromOutsideTargetSurface = false;
@@ -412,13 +414,14 @@ gfx::Rect OcclusionTrackerBase<LayerType, RenderSurfaceType>::unoccludedContentR
     // Take the ToEnclosingRect at each step, as we want to contain any unoccluded partial pixels in the resulting Rect.
     Region unoccludedRegionInTargetSurface = gfx::ToEnclosingRect(MathUtil::mapClippedRect(drawTransform, gfx::RectF(contentRect)));
     // Layers can't clip across surfaces, so count this as internal occlusion.
-    // TODO(danakj): This would change if we clipped to the visibleContentRect().
-    unoccludedRegionInTargetSurface.Intersect(clippedRectInTarget);
+    if (isClipped)
+      unoccludedRegionInTargetSurface.Intersect(clipRectInTarget);
     unoccludedRegionInTargetSurface.Subtract(m_stack.back().occlusionFromInsideTarget);
     gfx::RectF unoccludedRectInTargetSurfaceWithoutOutsideOcclusion = unoccludedRegionInTargetSurface.bounds();
     unoccludedRegionInTargetSurface.Subtract(m_stack.back().occlusionFromOutsideTarget);
 
     // Treat other clipping as occlusion from outside the surface.
+    // TODO(danakj): Clip to visibleContentRect?
     unoccludedRegionInTargetSurface.Intersect(renderTarget->renderSurface()->contentRect());
     unoccludedRegionInTargetSurface.Intersect(screenSpaceClipRectInTargetSurface(renderTarget->renderSurface(), m_screenSpaceClipRect));
 
@@ -471,7 +474,6 @@ gfx::Rect OcclusionTrackerBase<LayerType, RenderSurfaceType>::unoccludedContribu
     // Take the ToEnclosingRect at each step, as we want to contain any unoccluded partial pixels in the resulting Rect.
     Region unoccludedRegionInTargetSurface = gfx::ToEnclosingRect(MathUtil::mapClippedRect(drawTransform, gfx::RectF(contentRect)));
     // Layers can't clip across surfaces, so count this as internal occlusion.
-    // TODO(danakj): This would change if we clipped to the visibleContentRect().
     if (surface->isClipped())
         unoccludedRegionInTargetSurface.Intersect(surface->clipRect());
     if (hasOcclusion) {
@@ -500,14 +502,6 @@ gfx::Rect OcclusionTrackerBase<LayerType, RenderSurfaceType>::unoccludedContribu
     return unoccludedRect;
 }
 
-template<typename LayerType, typename RenderSurfaceType>
-gfx::Rect OcclusionTrackerBase<LayerType, RenderSurfaceType>::layerClipRectInTarget(const LayerType* layer) const
-{
-    // TODO(danakj): Can we remove this use of drawableContentRect and just use the clipRect() and target surface contentRect?
-    // TODO(danakj): Or can we use visibleContentRect() which is much tighter?
-    return layer->drawableContentRect();
-}
-
 // Instantiate (and export) templates here for the linker.
 template class OcclusionTrackerBase<Layer, RenderSurface>;
 template class OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl>;