Improve performance when calling PaintLayer::setNeedsRepaint()

third_party/WebKit/Source/core/layout/PaintInvalidationState.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/PaintInvalidationState.h"
 
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/svg/LayoutSVGModelObject.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/paint/PaintLayer.h"
 
 namespace blink {
 
 PaintInvalidationState::PaintInvalidationState(const LayoutView& layoutView, Vector<LayoutObject*>& pendingDelayedPaintInvalidations, PaintInvalidationState* ownerPaintInvalidationState)
     : m_clipped(false)
     , m_cachedOffsetsEnabled(true)
     , m_forcedSubtreeInvalidationWithinContainer(false)
     , m_forcedSubtreeInvalidationRectUpdateWithinContainer(false)
     , m_viewClippingAndScrollOffsetDisabled(false)
     , m_paintInvalidationContainer(layoutView.containerForPaintInvalidation())
     , m_pendingDelayedPaintInvalidations(pendingDelayedPaintInvalidations)
+    , m_enclosingLayer(*layoutView.layer())
 {
     bool establishesPaintInvalidationContainer = layoutView == m_paintInvalidationContainer;
     if (!establishesPaintInvalidationContainer) {
         if ((ownerPaintInvalidationState && !ownerPaintInvalidationState->m_cachedOffsetsEnabled)
             || !layoutView.supportsPaintInvalidationStateCachedOffsets()) {
             m_cachedOffsetsEnabled = false;
             return;
         }
         if (ownerPaintInvalidationState && ownerPaintInvalidationState->m_forcedSubtreeInvalidationWithinContainer)
             m_forcedSubtreeInvalidationWithinContainer = true;
         FloatPoint point = layoutView.localToAncestorPoint(FloatPoint(), &m_paintInvalidationContainer, TraverseDocumentBoundaries);
         m_paintOffset = LayoutSize(point.x(), point.y());
     }
     m_clipRect = layoutView.viewRect();
     m_clipRect.move(m_paintOffset);
     m_clipped = true;
 }
 
 PaintInvalidationState::PaintInvalidationState(PaintInvalidationState& next, LayoutBoxModelObject& layoutObject, const LayoutBoxModelObject& paintInvalidationContainer)
     : m_clipped(false)
     , m_cachedOffsetsEnabled(true)
     , m_forcedSubtreeInvalidationWithinContainer(next.m_forcedSubtreeInvalidationWithinContainer)
     , m_forcedSubtreeInvalidationRectUpdateWithinContainer(next.m_forcedSubtreeInvalidationRectUpdateWithinContainer)
     , m_viewClippingAndScrollOffsetDisabled(false)
     , m_paintInvalidationContainer(paintInvalidationContainer)
     , m_pendingDelayedPaintInvalidations(next.pendingDelayedPaintInvalidationTargets())
+    , m_enclosingLayer(next.enclosingLayer(layoutObject))
 {
     // FIXME: SVG could probably benefit from a stack-based optimization like html does. crbug.com/391054
     bool establishesPaintInvalidationContainer = layoutObject == m_paintInvalidationContainer;
     bool fixed = layoutObject.style()->position() == FixedPosition;
 
     if (!layoutObject.supportsPaintInvalidationStateCachedOffsets() || !next.m_cachedOffsetsEnabled)
         m_cachedOffsetsEnabled = false;
     if (establishesPaintInvalidationContainer) {
         // When we hit a new paint invalidation container, we don't need to
         // continue forcing a check for paint invalidation, since we're
@@ skipping 41 matching lines @@
 PaintInvalidationState::PaintInvalidationState(PaintInvalidationState& next, const LayoutSVGModelObject& layoutObject)
     : m_clipped(next.m_clipped)
     , m_cachedOffsetsEnabled(next.m_cachedOffsetsEnabled)
     , m_forcedSubtreeInvalidationWithinContainer(next.m_forcedSubtreeInvalidationWithinContainer)
     , m_forcedSubtreeInvalidationRectUpdateWithinContainer(next.m_forcedSubtreeInvalidationRectUpdateWithinContainer)
     , m_viewClippingAndScrollOffsetDisabled(false)
     , m_clipRect(next.m_clipRect)
     , m_paintOffset(next.m_paintOffset)
     , m_paintInvalidationContainer(next.m_paintInvalidationContainer)
     , m_pendingDelayedPaintInvalidations(next.pendingDelayedPaintInvalidationTargets())
+    , m_enclosingLayer(next.enclosingLayer(layoutObject))
 {
     ASSERT(layoutObject != m_paintInvalidationContainer);
 
     if (m_cachedOffsetsEnabled)
         m_svgTransform = AffineTransform(next.svgTransform() * layoutObject.localToParentTransform());
 }
 
 void PaintInvalidationState::addClipRectRelativeToPaintOffset(const LayoutSize& clipSize)
 {
     LayoutRect clipRect(toPoint(m_paintOffset), clipSize);
@@ skipping 15 matching lines @@
     // Do not clip scroll layer contents because the compositor expects the whole layer
     // to be always invalidated in-time.
     if (box.usesCompositedScrolling())
         ASSERT(!m_clipped); // The box should establish paint invalidation container, so no m_clipped inherited.
     else
         addClipRectRelativeToPaintOffset(LayoutSize(box.layer()->size()));
 
     m_paintOffset -= box.scrolledContentOffset();
 }
 
+PaintLayer& PaintInvalidationState::enclosingLayer(const LayoutObject& layoutObject) const
+{
+    if (layoutObject.hasLayer())
+        return *toLayoutBoxModelObject(layoutObject).layer();
+
+    // During paint invalidation, a multi-column spanner place holder invokes paint invalidation of
+    // its layoutObjectInFlowThread (which has a non-null spannerPlaceHolder) directly, skipping the
+    // parent of its layoutObjectInFlowThread which has a PaintLayer.
+    if (layoutObject.spannerPlaceholder())
+        return *layoutObject.enclosingLayer();
+
+    ASSERT(layoutObject.enclosingLayer() == &m_enclosingLayer);
+    return m_enclosingLayer;
+}
+
 } // namespace blink