Simplify and speed up painting of clipping masks

third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp

Index: third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
diff --git a/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp b/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
index bd8878a302b1dba1b02acd1c370850ad6cce395d..6c69213ab16795373cd266a1f580b43d11e65b4c 100644
--- a/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
+++ b/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
@@ -27,16 +27,14 @@ LayerClipRecorder::LayerClipRecorder(
     : m_graphicsContext(graphicsContext),
       m_layoutObject(layoutObject),
       m_clipType(clipType) {
-  IntRect snappedClipRect = pixelSnappedIntRect(clipRect.rect());
-  Vector<FloatRoundedRect> roundedRects;
+  m_snappedClipRect = pixelSnappedIntRect(clipRect.rect());
   if (localPaintingInfo && clipRect.hasRadius()) {
     collectRoundedRectClips(*layoutObject.layer(), *localPaintingInfo,
-                            graphicsContext, fragmentOffset, paintFlags, rule,
-                            roundedRects);
+                            graphicsContext, fragmentOffset, paintFlags, rule);
   }
 
   m_graphicsContext.getPaintController().createAndAppend<ClipDisplayItem>(
-      layoutObject, m_clipType, snappedClipRect, roundedRects);
+      layoutObject, m_clipType, m_snappedClipRect, m_roundedRects);
 }
 
 static bool inContainingBlockChain(PaintLayer* startLayer,
@@ -62,8 +60,7 @@ void LayerClipRecorder::collectRoundedRectClips(
     GraphicsContext& context,
     const LayoutPoint& fragmentOffset,
     PaintLayerFlags paintFlags,
-    BorderRadiusClippingRule rule,
-    Vector<FloatRoundedRect>& roundedRectClips) {
+    BorderRadiusClippingRule rule) {
   // If the clip rect has been tainted by a border radius, then we have to walk
   // up our layer chain applying the clips from any layers with overflow. The
   // condition for being able to apply these clips is that the overflow object
@@ -94,7 +91,7 @@ void LayerClipRecorder::collectRoundedRectClips(
       LayoutSize size(layer->layoutBox()
                           ? toLayoutBox(layer->layoutObject())->size()
                           : LayoutSize(layer->size()));
-      roundedRectClips.append(
+      m_roundedRects.append(
           layer->layoutObject()->style()->getRoundedInnerBorderFor(
               LayoutRect(delta, size)));
     }