Make PaintLayerClipper objects transient

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>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 81 matching lines @@
 
 namespace blink {
 
 namespace {
 
 static CompositingQueryMode gCompositingQueryMode =
     CompositingQueriesAreOnlyAllowedInCertainDocumentLifecyclePhases;
 
 struct SameSizeAsPaintLayer : DisplayItemClient {
     int bitFields;
-    void* pointers[8];
+    void* pointers[9];
     LayoutUnit layoutUnits[4];
     IntSize size;
     OwnPtrWillBePersistent<PaintLayerScrollableArea> scrollableArea;
     struct {
         IntRect rect;
         void* pointers[2];
     } ancestorCompositingInputs;
     struct {
-        void* pointers[2];
-    } clipper;
-    struct {
         IntSize size;
         void* pointer;
         LayoutRect rect;
     } previousPaintStatus;
 };
 
 static_assert(sizeof(PaintLayer) == sizeof(SameSizeAsPaintLayer), "PaintLayer should stay small");
 
 } // namespace
 
@@ skipping 42 matching lines @@
     , m_hasNonIsolatedDescendantWithBlendMode(false)
     , m_hasAncestorWithClipPath(false)
     , m_layoutObject(layoutObject)
     , m_parent(0)
     , m_previous(0)
     , m_next(0)
     , m_first(0)
     , m_last(0)
     , m_staticInlinePosition(0)
     , m_staticBlockPosition(0)
-    , m_clipper(*layoutObject)
 {
     updateStackingNode();
 
     m_isSelfPaintingLayer = shouldBeSelfPaintingLayer();
 
     if (!layoutObject->slowFirstChild() && layoutObject->style()) {
         m_visibleContentStatusDirty = false;
         m_hasVisibleContent = layoutObject->style()->visibility() == VISIBLE;
     }
 
@@ skipping 97 matching lines @@
 void PaintLayer::setSubpixelAccumulation(const LayoutSize& size)
 {
     if (m_rareData || !size.isZero())
         ensureRareData().subpixelAccumulation = size;
 }
 
 void PaintLayer::updateLayerPositionsAfterLayout()
 {
     TRACE_EVENT0("blink,benchmark", "PaintLayer::updateLayerPositionsAfterLayout");
 
-    m_clipper.clearClipRectsIncludingDescendants();
+    clipper().clearClipRectsIncludingDescendants();
     updateLayerPositionRecursive();
 
     {
         // FIXME: Remove incremental compositing updates after fixing the chicken/egg issues
         // https://code.google.com/p/chromium/issues/detail?id=343756
         DisableCompositingQueryAsserts disabler;
         updatePaginationRecursive(enclosingPaginationLayer());
     }
 }
 
@@ skipping 56 matching lines @@
 
 bool PaintLayer::scrollsWithRespectTo(const PaintLayer* other) const
 {
     if (scrollsWithViewport() != other->scrollsWithViewport())
         return true;
     return ancestorScrollingLayer() != other->ancestorScrollingLayer();
 }
 
 void PaintLayer::updateLayerPositionsAfterOverflowScroll(const DoubleSize& scrollDelta)
 {
-    m_clipper.clearClipRectsIncludingDescendants();
+    clipper().clearClipRectsIncludingDescendants();
     updateLayerPositionsAfterScrollRecursive(scrollDelta, isPaintInvalidationContainer());
 }
 
 void PaintLayer::updateLayerPositionsAfterScrollRecursive(const DoubleSize& scrollDelta, bool paintInvalidationContainerWasScrolled)
 {
     updateLayerPosition();
     if (paintInvalidationContainerWasScrolled && !isPaintInvalidationContainer()) {
         // Paint invalidation rects are in the coordinate space of the paint invalidation container.
         // If it has scrolled, the rect must be adjusted. Note that it is not safe to reset it to
         // the current bounds rect, as the LayoutObject may have moved since the last invalidation.
@@ skipping 29 matching lines @@
     bool had3DTransform = has3DTransform();
 
     bool hadTransform = transform();
     if (hasTransform != hadTransform) {
         if (hasTransform)
             ensureRareData().transform = adoptPtr(new TransformationMatrix);
         else
             m_rareData->transform.clear();
 
         // PaintLayers with transforms act as clip rects roots, so clear the cached clip rects here.
-        m_clipper.clearClipRectsIncludingDescendants();
+        clipper().clearClipRectsIncludingDescendants();
     } else if (hasTransform) {
-        m_clipper.clearClipRectsIncludingDescendants(AbsoluteClipRects);
+        clipper().clearClipRectsIncludingDescendants(AbsoluteClipRects);
     }
 
     updateTransformationMatrix();
 
     if (had3DTransform != has3DTransform())
         dirty3DTransformedDescendantStatus();
 }
 
 static PaintLayer* enclosingLayerForContainingBlock(PaintLayer* layer)
 {
@@ skipping 828 matching lines @@
         if (isPaintInvalidationContainer()) {
             // Our children will be reparented and contained by a new paint invalidation container,
             // so need paint invalidation. CompositingUpdate can't see this layer (which has been
             // removed) so won't do this for us.
             DisablePaintInvalidationStateAsserts disabler;
             layoutObject()->invalidatePaintIncludingNonCompositingDescendants();
             layoutObject()->setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants();
         }
     }
 
-    m_clipper.clearClipRectsIncludingDescendants();
+    clipper().clearClipRectsIncludingDescendants();
 
     PaintLayer* nextSib = nextSibling();
 
     // Remove the child reflection layer before moving other child layers.
     // The reflection layer should not be moved to the parent.
     if (PaintLayerReflectionInfo* reflectionInfo = this->reflectionInfo())
         removeChild(reflectionInfo->reflectionLayer());
 
     // Now walk our kids and reattach them to our parent.
     PaintLayer* current = m_first;
@@ skipping 21 matching lines @@
         ASSERT(parentLayer);
         PaintLayer* beforeChild = !parentLayer->reflectionInfo() || parentLayer->reflectionInfo()->reflectionLayer() != this ? layoutObject()->parent()->findNextLayer(parentLayer, layoutObject()) : 0;
         parentLayer->addChild(this, beforeChild);
     }
 
     // Remove all descendant layers from the hierarchy and add them to the new position.
     for (LayoutObject* curr = layoutObject()->slowFirstChild(); curr; curr = curr->nextSibling())
         curr->moveLayers(m_parent, this);
 
     // Clear out all the clip rects.
-    m_clipper.clearClipRectsIncludingDescendants();
+    clipper().clearClipRectsIncludingDescendants();
 }
 
 // Returns the layer reached on the walk up towards the ancestor.
 static inline const PaintLayer* accumulateOffsetTowardsAncestor(const PaintLayer* layer, const PaintLayer* ancestorLayer, LayoutPoint& location)
 {
     ASSERT(ancestorLayer != layer);
 
     const LayoutBoxModelObject* layoutObject = layer->layoutObject();
     EPosition position = layoutObject->style()->position();
 
@@ skipping 1555 matching lines @@
 
 void showLayerTree(const blink::LayoutObject* layoutObject)
 {
     if (!layoutObject) {
         fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
         return;
     }
     showLayerTree(layoutObject->enclosingLayer());
 }
 #endif