Ensure paint properties are rebuilt on window resizes

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 2e8b893a56c61e0cb3f56a55d77d91fe29deac6d..128f3c0ad2aedbef48743d89a4161bf9609c0449 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -651,12 +651,6 @@ 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() {
@@ -3568,6 +3562,11 @@ void FrameView::frameRectsChanged() {
     setLayoutSizeInternal(frameRect().size());
 
   setNeedsUpdateViewportIntersection();
+  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {

[Xianzhu, 2016/11/27 18:00:04]

slimmingPaintInvalidationEnabled?

[pdr., 2016/11/28 03:15:05]

I've been using RuntimeEnabledFeatures::slimmingPaintV2Enabled for the paint
property tree invalidation work so far, but that may have been a mistake. Should
it be behind RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled? If so,
which parts should be slimmingPaintInvalidationEnabled vs
slimmingPaintV2Enabled?

[Xianzhu, 2016/11/28 17:56:00]

Oh, I didn't notice this before. We should use slimmingPaintInvalidationEnabled
where it's guarding property tree building.

+    // The overflow clip property depends on the frame rect.
+    setNeedsPaintPropertyUpdate();
+  }
+
   for (const auto& child : m_children)
     child->frameRectsChanged();
 }