Improve performance when calling PaintLayer::setNeedsRepaint()

third_party/WebKit/Source/core/layout/PaintInvalidationState.h

 // 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.
 
 #ifndef PaintInvalidationState_h
 #define PaintInvalidationState_h
 
 #include "platform/geometry/LayoutRect.h"
 #include "platform/transforms/AffineTransform.h"
 #include "wtf/Allocator.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class LayoutBoxModelObject;
 class LayoutObject;
 class LayoutSVGModelObject;
 class LayoutView;
+class PaintLayer;
 
 // PaintInvalidationState is an optimization used during the paint
 // invalidation phase.
 //
 // This class is extremely close to LayoutState so see the documentation
 // of LayoutState for the class existence and performance benefits.
 //
 // The main difference with LayoutState is that it was customized for the
 // needs of the paint invalidation systems (keeping visual rectangles
 // instead of layout specific information).
@@ skipping 31 matching lines @@
 
     // Records |obj| as needing paint invalidation on the next frame. See the definition of PaintInvalidationDelayedFull for more details.
     void pushDelayedPaintInvalidationTarget(LayoutObject& obj) { m_pendingDelayedPaintInvalidations.append(&obj); }
     Vector<LayoutObject*>& pendingDelayedPaintInvalidationTargets() { return m_pendingDelayedPaintInvalidations; }
 
     // Disable view clipping and scroll offset adjustment for paint invalidation of FrameView scrollbars.
     // TODO(wangxianzhu): Remove this when root-layer-scrolls launches.
     bool viewClippingAndScrollOffsetDisabled() const { return m_viewClippingAndScrollOffsetDisabled; }
     void setViewClippingAndScrollOffsetDisabled(bool b) { m_viewClippingAndScrollOffsetDisabled = b; }
 
+    PaintLayer& enclosingLayer(const LayoutObject&) const;
+
 private:
     PaintInvalidationState(const LayoutView&, Vector<LayoutObject*>& pendingDelayedPaintInvalidations, PaintInvalidationState* ownerPaintInvalidationState);
 
     void applyClipIfNeeded(const LayoutObject&);
     void addClipRectRelativeToPaintOffset(const LayoutSize& clipSize);
 
     friend class ForceHorriblySlowRectMapping;
 
     bool m_clipped;
     mutable bool m_cachedOffsetsEnabled;
@@ skipping 10 matching lines @@
     //
     // It is the enclosing composited object.
     const LayoutBoxModelObject& m_paintInvalidationContainer;
 
     // Transform from the initial viewport coordinate system of an outermost
     // SVG root to the userspace _before_ the relevant element. Combining this
     // with |m_paintOffset| yields the "final" offset.
     AffineTransform m_svgTransform;
 
     Vector<LayoutObject*>& m_pendingDelayedPaintInvalidations;
+
+    PaintLayer& m_enclosingLayer;
 };
 
 } // namespace blink
 
 #endif // PaintInvalidationState_h