Improve performance when calling PaintLayer::setNeedsRepaint()

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

Index: third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
diff --git a/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp b/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
index 86d5be22199f4895838dfab82c3ffd4eef60d642..23d8fa55e08bfee7b607b5a15f7ec5d227b004bb 100644
--- a/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
+++ b/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
@@ -20,6 +20,7 @@ PaintInvalidationState::PaintInvalidationState(const LayoutView& layoutView, Vec
     , m_viewClippingAndScrollOffsetDisabled(false)
     , m_paintInvalidationContainer(layoutView.containerForPaintInvalidation())
     , m_pendingDelayedPaintInvalidations(pendingDelayedPaintInvalidations)
+    , m_enclosingLayer(*layoutView.layer())
 {
     bool establishesPaintInvalidationContainer = layoutView == m_paintInvalidationContainer;
     if (!establishesPaintInvalidationContainer) {
@@ -46,6 +47,7 @@ PaintInvalidationState::PaintInvalidationState(PaintInvalidationState& next, Lay
     , 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;
@@ -107,6 +109,7 @@ PaintInvalidationState::PaintInvalidationState(PaintInvalidationState& next, con
     , m_paintOffset(next.m_paintOffset)
     , m_paintInvalidationContainer(next.m_paintInvalidationContainer)
     , m_pendingDelayedPaintInvalidations(next.pendingDelayedPaintInvalidationTargets())
+    , m_enclosingLayer(next.enclosingLayer(layoutObject))
 {
     ASSERT(layoutObject != m_paintInvalidationContainer);
 
@@ -142,4 +145,19 @@ void PaintInvalidationState::applyClipIfNeeded(const LayoutObject& layoutObject)
     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