Reduce copying of local data structures in GeometryMapper and PaintLayerClipper.

third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/compositing/CompositingInputsUpdater.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutBlock.h"
@@ skipping 143 matching lines @@
       if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
         properties.unclippedAbsoluteBoundingBox =
             enclosingIntRect(m_geometryMap.absoluteRect(
                 FloatRect(layer->boundingBoxForCompositingOverlapTest())));
         // FIXME: Setting the absBounds to 1x1 instead of 0x0 makes very little
         // sense, but removing this code will make JSGameBench sad.
         // See https://codereview.chromium.org/13912020/
         if (properties.unclippedAbsoluteBoundingBox.isEmpty())
           properties.unclippedAbsoluteBoundingBox.setSize(IntSize(1, 1));
 
-        IntRect clipRect = pixelSnappedIntRect(
-            layer->clipper(PaintLayer::DoNotUseGeometryMapper)
-                .backgroundClipRect(
-                    ClipRectsContext(m_rootLayer, AbsoluteClipRects))
-                .rect());
+        ClipRect clipRect;
+        layer->clipper(PaintLayer::DoNotUseGeometryMapper)
+            .calculateBackgroundClipRect(
+                ClipRectsContext(m_rootLayer, AbsoluteClipRects), clipRect);
+        IntRect snappedClipRect = pixelSnappedIntRect(clipRect.rect());
         properties.clippedAbsoluteBoundingBox =
             properties.unclippedAbsoluteBoundingBox;
-        properties.clippedAbsoluteBoundingBox.intersect(clipRect);
+        properties.clippedAbsoluteBoundingBox.intersect(snappedClipRect);
       }
 
       const PaintLayer* parent = layer->parent();
       properties.opacityAncestor =
           parent->isTransparent() ? parent : parent->opacityAncestor();
       properties.transformAncestor =
           parent->transform() ? parent : parent->transformAncestor();
       properties.filterAncestor = parent->hasFilterInducingProperty()
                                       ? parent
                                       : parent->filterAncestor();
@@ skipping 90 matching lines @@
   ASSERT(!layer->needsCompositingInputsUpdate());
 
   for (PaintLayer* child = layer->firstChild(); child;
        child = child->nextSibling())
     assertNeedsCompositingInputsUpdateBitsCleared(child);
 }
 
 #endif
 
 }  // namespace blink