Implement incremental paint property tree rebuilding

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index a3537839378bfed23940dbbef65496c9484447bf..e4722def6afc0c5f43b28181d138eccbc8366979 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -184,6 +184,7 @@ FrameView::FrameView(LocalFrame* frame)
       m_hiddenForThrottling(false),
       m_crossOriginForThrottling(false),
       m_subtreeThrottled(false),
+      m_needsPaintPropertyUpdate(true),
       m_currentUpdateLifecyclePhasesTargetState(
           DocumentLifecycle::Uninitialized),
       m_scrollAnchor(this),
@@ -606,6 +607,12 @@ void FrameView::setContentsSize(const IntSize& size) {
 
   page->chromeClient().contentsSizeChanged(m_frame.get(), size);
   frame().loader().restoreScrollPositionAndViewState();
+
+  if (!RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
+    // The presence of overflow depends on the contents size. The scroll
+    // properties can change depending on whether overflow scrolling occurs.
+    setNeedsPaintPropertyUpdate();
+  }
 }
 
 void FrameView::adjustViewSize() {
@@ -3638,6 +3645,11 @@ void FrameView::didChangeScrollOffset() {
   frame().loader().client()->didChangeScrollOffset();
   if (frame().isMainFrame())
     frame().host()->chromeClient().mainFrameScrollOffsetChanged();
+
+  if (!RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
+    // The scroll translation paint property depends on scroll offset.
+    setNeedsPaintPropertyUpdate();
+  }
 }
 
 void FrameView::clearScrollAnchor() {