Reduce copying of local data structures in GeometryMapper and PaintLayerClipper.

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 1628 matching lines @@
   // intersect with that when painting column contents.
   ClipRect ancestorClipRect = dirtyRect;
   if (const PaintLayer* paginationParentLayer =
           enclosingPaginationLayer()->parent()) {
     const PaintLayer* ancestorLayer =
         rootLayerIsInsidePaginationLayer ? paginationParentLayer : rootLayer;
     ClipRectsContext clipRectsContext(ancestorLayer, clipRectsCacheSlot,
                                       overlayScrollbarClipBehavior);
     if (respectOverflowClip == IgnoreOverflowClip)
       clipRectsContext.setIgnoreOverflowClip();
-    ancestorClipRect = enclosingPaginationLayer()
-                           ->clipper(geometryMapperOption)
-                           .backgroundClipRect(clipRectsContext);
+
+    enclosingPaginationLayer()
+        ->clipper(geometryMapperOption)
+        .calculateBackgroundClipRect(clipRectsContext, ancestorClipRect);
     if (rootLayerIsInsidePaginationLayer)
       ancestorClipRect.moveBy(
           -rootLayer->visualOffsetFromAncestor(ancestorLayer));
     ancestorClipRect.intersect(dirtyRect);
   }
 
   const LayoutSize subPixelAccumulationIfNeeded =
       offsetFromRoot ? subPixelAccumulation : LayoutSize();
   for (; !iterator.atEnd(); iterator.advance()) {
     PaintLayerFragment fragment;
@@ skipping 230 matching lines @@
 
   // Apply a transform if we have one.
   if (transform() && !appliedTransform) {
     if (enclosingPaginationLayer())
       return hitTestTransformedLayerInFragments(
           rootLayer, containerLayer, result, hitTestRect, hitTestLocation,
           transformState, zOffset, clipRectsCacheSlot);
 
     // Make sure the parent's clip rects have been calculated.
     if (parent()) {
-      ClipRect clipRect = clipper(PaintLayer::DoNotUseGeometryMapper)
-                              .backgroundClipRect(ClipRectsContext(
-                                  rootLayer, clipRectsCacheSlot,
-                                  ExcludeOverlayScrollbarSizeForHitTesting));
+      ClipRect clipRect;
+      clipper(PaintLayer::DoNotUseGeometryMapper)
+          .calculateBackgroundClipRect(
+              ClipRectsContext(rootLayer, clipRectsCacheSlot,
+                               ExcludeOverlayScrollbarSizeForHitTesting),
+              clipRect);
       // Go ahead and test the enclosing clip now.
       if (!clipRect.intersects(hitTestLocation))
         return nullptr;
     }
 
     return hitTestLayerByApplyingTransform(rootLayer, containerLayer, result,
                                            hitTestRect, hitTestLocation,
                                            transformState, zOffset);
   }
 
@@ skipping 218 matching lines @@
     const PaintLayerFragment& fragment = enclosingPaginationFragments.at(i);
 
     // Apply the page/column clip for this fragment, as well as any clips
     // established by layers in between us and the enclosing pagination layer.
     LayoutRect clipRect = fragment.backgroundRect.rect();
 
     // Now compute the clips within a given fragment
     if (parent() != enclosingPaginationLayer()) {
       enclosingPaginationLayer()->convertToLayerCoords(
           rootLayer, offsetOfPaginationLayerFromRoot);
-      LayoutRect parentClipRect =
-          clipper(PaintLayer::DoNotUseGeometryMapper)
-              .backgroundClipRect(ClipRectsContext(
-                  enclosingPaginationLayer(), clipRectsCacheSlot,
-                  ExcludeOverlayScrollbarSizeForHitTesting))
-              .rect();
+
+      ClipRect parentClipRect;
+      clipper(PaintLayer::DoNotUseGeometryMapper)
+          .calculateBackgroundClipRect(
+              ClipRectsContext(enclosingPaginationLayer(), clipRectsCacheSlot,
+                               ExcludeOverlayScrollbarSizeForHitTesting),
+              parentClipRect);
+
       parentClipRect.moveBy(fragment.paginationOffset +
                             offsetOfPaginationLayerFromRoot);
-      clipRect.intersect(parentClipRect);
+      clipRect.intersect(parentClipRect.rect());
     }
 
     if (!hitTestLocation.intersects(clipRect))
       continue;
 
     PaintLayer* hitLayer = hitTestLayerByApplyingTransform(
         rootLayer, containerLayer, result, hitTestRect, hitTestLocation,
         transformState, zOffset, fragment.paginationOffset);
     if (hitLayer)
       return hitLayer;
@@ skipping 1064 matching lines @@
 }
 
 void showLayerTree(const blink::LayoutObject* layoutObject) {
   if (!layoutObject) {
     LOG(INFO) << "Cannot showLayerTree. Root is (nil)";
     return;
   }
   showLayerTree(layoutObject->enclosingLayer());
 }
 #endif