Clean up GraphicsLayerPaintInfo to remove unused or unnecessary fields.

Source/core/rendering/RenderText.cpp

Index: Source/core/rendering/RenderText.cpp
diff --git a/Source/core/rendering/RenderText.cpp b/Source/core/rendering/RenderText.cpp
index 1170cddfc7c91f7dbcc921b0c483092966cd6e6f..4a2aab7d5a37cb0b0d6c09feb97204403945914b 100644
--- a/Source/core/rendering/RenderText.cpp
+++ b/Source/core/rendering/RenderText.cpp
@@ -1576,20 +1576,29 @@ LayoutRect RenderText::linesVisualOverflowBoundingBox() const
 
 LayoutRect RenderText::clippedOverflowRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, const PaintInvalidationState* paintInvalidationState) const
 {
+    const RenderObject* rendererToIssuePaintInvalidations = containingObjectForPaintInvalidation();
+    return rendererToIssuePaintInvalidations->clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
+}
+
+const RenderObject* RenderText::containingObjectForPaintInvalidation() const
+{
     RenderObject* rendererToIssuePaintInvalidations = containingBlock();
 
     // Do not cross self-painting layer boundaries.
     RenderObject* enclosingLayerRenderer = enclosingLayer()->renderer();
     if (enclosingLayerRenderer != rendererToIssuePaintInvalidations && !rendererToIssuePaintInvalidations->isDescendantOf(enclosingLayerRenderer))
         rendererToIssuePaintInvalidations = enclosingLayerRenderer;
+    return enclosingLayerRenderer;
+}
 
-    // The renderer we chose to issue paint invalidations may be an ancestor of paintInvalidationContainer, but we need to do a paintInvalidationContainer-relative paint invalidation.
-    if (paintInvalidationContainer && paintInvalidationContainer != rendererToIssuePaintInvalidations && !rendererToIssuePaintInvalidations->isDescendantOf(paintInvalidationContainer))
-        return paintInvalidationContainer->clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
-
-    return rendererToIssuePaintInvalidations->clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
+const RenderLayerModelObject* RenderText::containerForPaintInvalidation() const
+{
+    const RenderObject* rendererToIssuePaintInvalidations = containingObjectForPaintInvalidation();
+    ASSERT(rendererToIssuePaintInvalidations);
+    return rendererToIssuePaintInvalidations->containerForPaintInvalidation();
 }
 
+
 LayoutRect RenderText::selectionRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, bool clipToVisibleContent)
 {
     ASSERT(!needsLayout());