Move RenderLayer repainting to repaint-after-layout framework.

Source/core/rendering/RenderLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 311 matching lines @@
 }
 
 int RenderLayerScrollableArea::scrollSize(ScrollbarOrientation orientation) const
 {
     IntSize scrollDimensions = maximumScrollPosition() - minimumScrollPosition();
     return (orientation == HorizontalScrollbar) ? scrollDimensions.width() : scrollDimensions.height();
 }
 
 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)
             computeScrollDimensions();
     }
 
     if (scrollOffset() == toIntSize(newScrollOffset))
         return;
 
     setScrollOffset(toIntSize(newScrollOffset));
@@ skipping 16 matching lines @@
         // for now we just crash to avoid allowing an attacker to use after free.
         frameView->updateWidgetPositions();
         RELEASE_ASSERT(frameView->renderView());
         updateCompositingLayersAfterScroll();
     }
 
     RenderLayerModelObject* repaintContainer = m_box->containerForRepaint();
     // 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);
 
     bool requiresRepaint = true;
 
     if (m_box->view()->compositor()->inCompositingMode()) {
         bool onlyScrolledCompositedLayers = scrollsOverflow()
             && !layer()->hasVisibleNonLayerContent()
             && !layer()->hasNonCompositedChild()
             && !layer()->hasBlockSelectionGapBounds()
             && !m_box->isMarquee();
 
         if (usesCompositedScrolling() || onlyScrolledCompositedLayers)
             requiresRepaint = false;
     }
 
     // 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.
     if (m_box->node())
         m_box->node()->document().enqueueScrollEventForNode(m_box->node());
 
     if (AXObjectCache* cache = m_box->document().existingAXObjectCache())
         cache->handleScrollPositionChanged(m_box);
 
     InspectorInstrumentation::didScrollLayer(m_box);
@@ skipping 1109 matching lines @@
 void RenderLayerScrollableArea::setForceNeedsCompositedScrolling(ForceNeedsCompositedScrollingMode mode)
 {
     if (m_forceNeedsCompositedScrolling == mode)
         return;
 
     m_forceNeedsCompositedScrolling = mode;
     layer()->didUpdateNeedsCompositedScrolling();
 }
 
 } // Namespace WebCore