Skip paint property update and visual rect update if no geometry change

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/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutInline.h"
@@ skipping 612 matching lines @@
   LOG(ERROR) << "Fast path visual rect differs from slow path: fast: "
              << fastPathRect.toString()
              << " vs slow: " << slowPathRect.toString();
   showLayoutTree(&m_currentObject);
 
   NOTREACHED();
 }
 
 #endif  // CHECK_FAST_PATH_SLOW_PATH_EQUALITY
 
-static const PaintPropertyTreeBuilderContext& dummyTreeBuilderContext() {
-  DEFINE_STATIC_LOCAL(PaintPropertyTreeBuilderContext, dummyContext, ());
-  return dummyContext;
-}
-
 static GeometryMapper& dummyGeometryMapper() {
   DEFINE_STATIC_LOCAL(std::unique_ptr<GeometryMapper>, dummyMapper,
                       (GeometryMapper::create()));
   return *dummyMapper;
 }
 
 PaintInvalidatorContextAdapter::PaintInvalidatorContextAdapter(
     const PaintInvalidationState& paintInvalidationState)
-    // The dummy parameters will be never used because the overriding
+    // The dummy parameter will be never used because the overriding
     // mapLocalRectToVisualRectInBacking() uses PaintInvalidationState.
-    : PaintInvalidatorContext(dummyTreeBuilderContext(), dummyGeometryMapper()),
+    : PaintInvalidatorContext(nullptr, dummyGeometryMapper()),
       m_paintInvalidationState(paintInvalidationState) {
   forcedSubtreeInvalidationFlags =
       paintInvalidationState.m_forcedSubtreeInvalidationFlags;
   paintInvalidationContainer =
       &paintInvalidationState.paintInvalidationContainer();
   paintingLayer = &paintInvalidationState.paintingLayer();
 }
 
 void PaintInvalidatorContextAdapter::mapLocalRectToVisualRectInBacking(
     const LayoutObject& object,
     LayoutRect& rect) const {
   DCHECK(&object == &m_paintInvalidationState.currentObject());
   m_paintInvalidationState.mapLocalRectToVisualRectInBacking(rect);
 }
 
 }  // namespace blink