Optimize scroll adjustment for paint invalidation

third_party/WebKit/Source/core/layout/PaintInvalidationState.h

Index: third_party/WebKit/Source/core/layout/PaintInvalidationState.h
diff --git a/third_party/WebKit/Source/core/layout/PaintInvalidationState.h b/third_party/WebKit/Source/core/layout/PaintInvalidationState.h
index 74b2ce0899b123bea1cf6e1b4226b5a52a46d4ce..08f404969f310dea616de25a4db2e3eadc07dbd9 100644
--- a/third_party/WebKit/Source/core/layout/PaintInvalidationState.h
+++ b/third_party/WebKit/Source/core/layout/PaintInvalidationState.h
@@ -148,6 +148,11 @@ class CORE_EXPORT PaintInvalidationState {
   // It is the enclosing composited object.
   const LayoutBoxModelObject* m_paintInvalidationContainer;
 
+  // Adjusts scrolling contents coordinates in non-composited paint invalidation
+  // container into container coordinates. It's empty for non-scrolling or
+  // composited-scrolling paint invalidation container.
+  IntSize m_scrollAdjustment;
+
   // The current paint invalidation container for stacked contents (stacking
   // contexts or positioned objects).  It is the nearest ancestor composited
   // object which establishes a stacking context.  See