Move RenderLayer repainting to repaint-after-layout framework.

Source/core/rendering/RenderLayerScrollableArea.cpp

Index: Source/core/rendering/RenderLayerScrollableArea.cpp
diff --git a/Source/core/rendering/RenderLayerScrollableArea.cpp b/Source/core/rendering/RenderLayerScrollableArea.cpp
index 8684edbff0995ea22ffbacbb97e92502b678692c..8119a1d16cbafda5921c481787833ff0374ee3b6 100644
--- a/Source/core/rendering/RenderLayerScrollableArea.cpp
+++ b/Source/core/rendering/RenderLayerScrollableArea.cpp
@@ -329,6 +329,8 @@ int RenderLayerScrollableArea::scrollSize(ScrollbarOrientation orientation) cons
 
 void RenderLayerScrollableArea::setScrollOffset(const IntPoint& newScrollOffset)
 {
+    LayoutRectRecorder recorder(*m_box);
+
     if (!m_box->isMarquee()) {
         // Ensure that the dimensions will be computed if they need to be (for overflow:hidden blocks).
         if (m_scrollDimensionsDirty)
@@ -365,7 +367,12 @@ void RenderLayerScrollableArea::setScrollOffset(const IntPoint& newScrollOffset)
     // The caret rect needs to be invalidated after scrolling
     frame->selection().setCaretRectNeedsUpdate();
 
-    FloatQuad quadForFakeMouseMoveEvent = FloatQuad(layer()->repainter().repaintRect());
+    FloatQuad quadForFakeMouseMoveEvent;
+    if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled())
+        quadForFakeMouseMoveEvent = FloatQuad(layer()->renderer()->newRepaintRect());
+    else
+        quadForFakeMouseMoveEvent = FloatQuad(layer()->repainter().repaintRect());
+
     if (repaintContainer)
         quadForFakeMouseMoveEvent = repaintContainer->localToAbsoluteQuad(quadForFakeMouseMoveEvent);
     frame->eventHandler().dispatchFakeMouseMoveEventSoonInQuad(quadForFakeMouseMoveEvent);
@@ -385,10 +392,14 @@ void RenderLayerScrollableArea::setScrollOffset(const IntPoint& newScrollOffset)
 
     // Just schedule a full repaint of our object.
     if (requiresRepaint) {
-        if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && m_box->frameView()->isInPerformLayout())
-            m_box->setShouldDoFullRepaintAfterLayout(true);
-        else
+        if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
+            if (m_box->frameView()->isInPerformLayout())

[Julien - ping for review, 2014/03/04 18:22:10]

Why do we need to check isInPerformLayout() and why would it matter?

[dsinclair, 2014/03/04 19:21:52]

This code can be executed outside of layout. As far as I could tell, we need to
make sure we do the repaint in that case. So, if we're in layout we defer the
repaint, if we're not doing layout we allow the repaint to happen.

+                m_box->setShouldDoFullRepaintAfterLayout(true);
+            else
+                m_box->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(layer()->renderer()->newRepaintRect()));
+        } else {
             m_box->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(layer()->repainter().repaintRect()));
+        }
     }
 
     // Schedule the scroll DOM event.