cc: Stop converting Rect to QuadF to map to an enclosed rect.

cc/trees/occlusion_tracker.cc

Index: cc/trees/occlusion_tracker.cc
diff --git a/cc/trees/occlusion_tracker.cc b/cc/trees/occlusion_tracker.cc
index 1418b9359c512f8ef6103398a693211b0d5ea1f1..9ca733d2e77c0580c5c479e4119eadf6cad4dd92 100644
--- a/cc/trees/occlusion_tracker.cc
+++ b/cc/trees/occlusion_tracker.cc
@@ -84,12 +84,9 @@ static SimpleEnclosedRegion TransformSurfaceOpaqueRegion(
 
   SimpleEnclosedRegion transformed_region;
   for (size_t i = 0; i < region.GetRegionComplexity(); ++i) {
-    bool clipped;
-    gfx::QuadF transformed_quad =
-        MathUtil::MapQuad(transform, gfx::QuadF(region.GetRect(i)), &clipped);
+    // NonClippedRect is okay because we checked Preserves2dAxisAlignment above.
     gfx::Rect transformed_rect =
-        gfx::ToEnclosedRect(transformed_quad.BoundingBox());
-    DCHECK(!clipped);  // We only map if the transform preserves axis alignment.
+        MathUtil::MapEnclosedNonClippedRect(transform, region.GetRect(i));
     if (have_clip_rect)
       transformed_rect.Intersect(clip_rect_in_new_target);
     transformed_region.Union(transformed_rect);
@@ -432,14 +429,9 @@ void OcclusionTracker<LayerType>::MarkOccludedBehindLayer(
   }
 
   for (size_t i = 0; i < opaque_contents.GetRegionComplexity(); ++i) {
-    bool clipped;
-    gfx::QuadF transformed_quad =
-        MathUtil::MapQuad(layer->draw_transform(),
-                          gfx::QuadF(opaque_contents.GetRect(i)),
-                          &clipped);
-    gfx::Rect transformed_rect =
-        gfx::ToEnclosedRect(transformed_quad.BoundingBox());
-    DCHECK(!clipped);  // We only map if the transform preserves axis alignment.
+    // NonClippedRect is okay because we checked Preserves2dAxisAlignment above.
+    gfx::Rect transformed_rect = MathUtil::MapEnclosedNonClippedRect(
+        layer->draw_transform(), opaque_contents.GetRect(i));
     transformed_rect.Intersect(clip_rect_in_target);
     if (transformed_rect.width() < minimum_tracking_size_.width() &&
         transformed_rect.height() < minimum_tracking_size_.height())
@@ -450,13 +442,9 @@ void OcclusionTracker<LayerType>::MarkOccludedBehindLayer(
       continue;
 
     // Save the occluding area in screen space for debug visualization.
-    gfx::QuadF screen_space_quad = MathUtil::MapQuad(
+    gfx::Rect screen_space_rect = MathUtil::MapEnclosedClippedRect(
         layer->render_target()->render_surface()->screen_space_transform(),
-        gfx::QuadF(transformed_rect), &clipped);
-    // TODO(danakj): Store the quad in the debug info instead of the bounding
-    // box.
-    gfx::Rect screen_space_rect =
-        gfx::ToEnclosedRect(screen_space_quad.BoundingBox());
+        transformed_rect);
     occluding_screen_space_rects_->push_back(screen_space_rect);
   }
 
@@ -469,24 +457,16 @@ void OcclusionTracker<LayerType>::MarkOccludedBehindLayer(
   for (Region::Iterator non_opaque_content_rects(non_opaque_contents);
        non_opaque_content_rects.has_rect();
        non_opaque_content_rects.next()) {
-    // We've already checked for clipping in the MapQuad call above, these calls
-    // should not clip anything further.
-    gfx::Rect transformed_rect = gfx::ToEnclosedRect(
-        MathUtil::MapClippedRect(layer->draw_transform(),
-                                 gfx::RectF(non_opaque_content_rects.rect())));
+    // NonClippedRect is okay because we checked Preserves2dAxisAlignment above.
+    gfx::Rect transformed_rect = MathUtil::MapEnclosedNonClippedRect(
+        layer->draw_transform(), non_opaque_content_rects.rect());
     transformed_rect.Intersect(clip_rect_in_target);
     if (transformed_rect.IsEmpty())
       continue;
 
-    bool clipped;
-    gfx::QuadF screen_space_quad = MathUtil::MapQuad(
+    gfx::Rect screen_space_rect = MathUtil::MapEnclosedClippedRect(
         layer->render_target()->render_surface()->screen_space_transform(),
-        gfx::QuadF(transformed_rect),
-        &clipped);
-    // TODO(danakj): Store the quad in the debug info instead of the bounding
-    // box.
-    gfx::Rect screen_space_rect =
-        gfx::ToEnclosedRect(screen_space_quad.BoundingBox());
+        transformed_rect);
     non_occluding_screen_space_rects_->push_back(screen_space_rect);
   }
 }
@@ -520,7 +500,7 @@ bool OcclusionTracker<LayerType>::Occluded(
   if (!draw_transform.GetInverse(&inverse_draw_transform))
     return false;
 
-  // Take the ToEnclosingRect at each step, as we want to contain any unoccluded
+  // Take the EnclosingRect at each step, as we want to contain any unoccluded
   // partial pixels in the resulting Rect.
   gfx::Rect unoccluded_rect_in_target_surface =
       MathUtil::MapEnclosingClippedRect(draw_transform, content_rect);
@@ -554,7 +534,7 @@ gfx::Rect OcclusionTracker<LayerType>::UnoccludedContentRect(
   if (!draw_transform.GetInverse(&inverse_draw_transform))
     return content_rect;
 
-  // Take the ToEnclosingRect at each step, as we want to contain any unoccluded
+  // Take the EnclosingRect at each step, as we want to contain any unoccluded
   // partial pixels in the resulting Rect.
   gfx::Rect unoccluded_rect_in_target_surface =
       MathUtil::MapEnclosingClippedRect(draw_transform, content_rect);
@@ -600,7 +580,7 @@ gfx::Rect OcclusionTracker<LayerType>::UnoccludedContributingSurfaceContentRect(
   if (!draw_transform.GetInverse(&inverse_draw_transform))
     return content_rect;
 
-  // Take the ToEnclosingRect at each step, as we want to contain any unoccluded
+  // Take the EnclosingRect at each step, as we want to contain any unoccluded
   // partial pixels in the resulting Rect.
   gfx::Rect unoccluded_rect_in_target_surface =
       MathUtil::MapEnclosingClippedRect(draw_transform, content_rect);