Calculate correct clip foregroundBound and backgroundBound

Source/core/paint/DeprecatedPaintLayerClipper.cpp

Index: Source/core/paint/DeprecatedPaintLayerClipper.cpp
diff --git a/Source/core/paint/DeprecatedPaintLayerClipper.cpp b/Source/core/paint/DeprecatedPaintLayerClipper.cpp
index 4545e9497330e06859daee4296b23cb88f085714..4c97a90c674b665c7729f3a85267b6660fe3fbbd 100644
--- a/Source/core/paint/DeprecatedPaintLayerClipper.cpp
+++ b/Source/core/paint/DeprecatedPaintLayerClipper.cpp
@@ -227,10 +227,13 @@ void DeprecatedPaintLayerClipper::calculateRects(const ClipRectsContext& context
     outlineRect = backgroundRect;
 
     LayoutPoint offset;
-    if (offsetFromRoot)
+    if (offsetFromRoot) {
         offset = *offsetFromRoot;
-    else
+        foregroundRect.move(context.subPixelAccumulation);

[pdr., 2015/08/07 23:20:31]

Why don't we need to move backgroundRect too?

[qiankun, 2015/08/13 10:36:03]

Thanks for review. backgroundRect also needs to move. I updated the CL. Layout
test was added.  

+        outlineRect.move(context.subPixelAccumulation);
+    } else {
         m_layoutObject.layer()->convertToLayerCoords(context.rootLayer, offset);
+    }
     layerBounds = LayoutRect(offset, LayoutSize(m_layoutObject.layer()->size()));
 
     // Update the clip rects that will be passed to child layers.