Remove the HasOwnBackingButPaintsIntoAncestor compositing state.

Source/core/rendering/compositing/CompositingState.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CompositingState_h
 #define CompositingState_h
 
 namespace blink {
 
 enum CompositingState {
     // The layer paints into its enclosing composited ancestor.
     NotComposited = 0,
 
-    // The layer is composited, but its contents still paint into enclosing composited ancestor.
-    // In this state, paint invalidations must be sent to the enclosing composited ancestor.
-    // Typically this happens when a layer's properties need to be represented in the compositor
-    // output data structures, but it doesn't actually have any other reasons to be composited.
-    HasOwnBackingButPaintsIntoAncestor = 1,
-
-    PaintsIntoOwnBacking = 2,
+    PaintsIntoOwnBacking = 1,
 
     // In this state, the RenderLayer subtree paints into a backing that is shared by
     // several RenderLayer subtrees.
-    PaintsIntoGroupedBacking = 3
+    PaintsIntoGroupedBacking = 2
 };
 
 } // namespace blink
 
 #endif // CompositingState_h