[SPv2] FrameView::synchronizedPaint should apply root property nodes

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 e00f51476cdb872eb478c6c3c7e89273fa6f09c9..d0af7a85aac58829f00dc42a9fb85c671a651205 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -2634,8 +2634,21 @@ void FrameView::synchronizedPaint()
 
 void FrameView::synchronizedPaintRecursively(GraphicsLayer* graphicsLayer)
 {
-    if (graphicsLayer->drawsContent())
+    if (graphicsLayer->drawsContent()) {
+        // Usually this is not needed because the PaintLayer will setup the chunk properties

[pdr., 2016/07/13 02:26:51]

Can you wrap this in:
#ifndef NDEBUG

...

#endif

[trchen, 2016/07/13 02:50:39]

I'm thinking non-RLS scrollbars will need this too.

+        // altogether. However in debug builds the GraphicsLayer could paint debug background before
+        // we ever reach the PaintLayer.
+        if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {

[pdr., 2016/07/13 02:26:51]

Instead of special-casing this, is it possible to trigger a full update by
calling updatePaintProperties();?

[trchen, 2016/07/13 02:50:39]

We always have up-to-date property tree at this point so calling
updatePaintProperties() will be no-op.

This ensures none of the paint chunk property can be nullptr (which really meant
the root node).

+            PaintChunkProperties properties;
+            properties.transform = m_rootTransform;
+            properties.clip = m_rootClip;
+            properties.effect = m_rootEffect;
+            graphicsLayer->getPaintController().updateCurrentPaintChunkProperties(properties);
+        }
         graphicsLayer->paint(nullptr);
+        if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+            graphicsLayer->getPaintController().updateCurrentPaintChunkProperties(PaintChunkProperties());
+    }
 
     if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
         if (GraphicsLayer* maskLayer = graphicsLayer->maskLayer())