Merge 104782 - Repaint all graphics layers when their renderer offset changes

Source/WebCore/rendering/RenderLayerBacking.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 391 matching lines @@
         m_ancestorClippingLayer->setSize(parentClipRect.size());
 
         // backgroundRect is relative to compAncestor, so subtract deltaX/deltaY to get back to local coords.
         m_ancestorClippingLayer->setOffsetFromRenderer(parentClipRect.location() - delta);
 
         // The primary layer is then parented in, and positioned relative to this clipping layer.
         graphicsLayerParentLocation = parentClipRect.location();
     }
 
     m_graphicsLayer->setPosition(FloatPoint() + (relativeCompositingBounds.location() - graphicsLayerParentLocation));
-    
-    LayoutSize oldOffsetFromRenderer = m_graphicsLayer->offsetFromRenderer();
     m_graphicsLayer->setOffsetFromRenderer(localCompositingBounds.location() - LayoutPoint());
     
-    // If the compositing layer offset changes, we need to repaint.
-    if (oldOffsetFromRenderer != m_graphicsLayer->offsetFromRenderer())
-        m_graphicsLayer->setNeedsDisplay();
-    
     FloatSize oldSize = m_graphicsLayer->size();
     FloatSize newSize = relativeCompositingBounds.size();
     if (oldSize != newSize) {
         m_graphicsLayer->setSize(newSize);
         // A bounds change will almost always require redisplay. Usually that redisplay
         // will happen because of a repaint elsewhere, but not always:
         // e.g. see RenderView::setMaximalOutlineSize()
         m_graphicsLayer->setNeedsDisplay();
     }
 
@@ skipping 761 matching lines @@
     scrollbar->paint(&context, transformedClip);
     context.restore();
 }
 
 // Up-call from compositing layer drawing callback.
 void RenderLayerBacking::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase paintingPhase, const LayoutRect& clip)
 {
     if (graphicsLayer == m_graphicsLayer.get() || graphicsLayer == m_foregroundLayer.get() || graphicsLayer == m_maskLayer.get()) {
         InspectorInstrumentationCookie cookie = InspectorInstrumentation::willPaint(m_owningLayer->renderer()->frame(), clip);
 
-        LayoutSize offset = graphicsLayer->offsetFromRenderer();
-        context.translate(-offset);
-
-        LayoutRect clipRect(clip);
-        clipRect.move(offset);
-
         // The dirtyRect is in the coords of the painting root.
         LayoutRect dirtyRect = compositedBounds();
-        dirtyRect.intersect(clipRect);
+        dirtyRect.intersect(clip);
 
         // We have to use the same root as for hit testing, because both methods can compute and cache clipRects.
         paintIntoLayer(m_owningLayer, &context, dirtyRect, PaintBehaviorNormal, paintingPhase, renderer());
 
         InspectorInstrumentation::didPaint(cookie);
     } else if (graphicsLayer == layerForHorizontalScrollbar()) {
         paintScrollbar(m_owningLayer->horizontalScrollbar(), context, clip);
     } else if (graphicsLayer == layerForVerticalScrollbar()) {
         paintScrollbar(m_owningLayer->verticalScrollbar(), context, clip);
     } else if (graphicsLayer == layerForScrollCorner()) {
@@ skipping 238 matching lines @@
 
     if (m_graphicsLayer->drawsContent())
         return m_graphicsLayer->usingTiledLayer() ? TiledCompositingLayer : NormalCompositingLayer;
     
     return ContainerCompositingLayer;
 }
 
 } // namespace WebCore
 
 #endif // USE(ACCELERATED_COMPOSITING)