(WIP) Paint invalidation for slimming paint v2

Source/core/dom/DocumentLifecycle.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 165 matching lines @@
         break;
     case InCompositingUpdate:
         return nextState == CompositingClean;
     case CompositingClean:
         if (nextState == InStyleRecalc)
             return true;
         if (nextState == InPreLayout)
             return true;
         if (nextState == InCompositingUpdate)
             return true;
-        if (nextState == InPaintInvalidation)
+        if (nextState == InPaintInvalidation && !RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+            return true;
+        if (nextState == InPaintForSlimmingPaintV2 && RuntimeEnabledFeatures::slimmingPaintV2Enabled())
             return true;
         break;
     case InPaintInvalidation:
+        ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
         return nextState == PaintInvalidationClean;
     case PaintInvalidationClean:
+        ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
         if (nextState == InStyleRecalc)
             return true;
         if (nextState == InPreLayout)
             return true;
         if (nextState == InCompositingUpdate)
             return true;
         if (nextState == InPaintForSlimmingPaintV2 && RuntimeEnabledFeatures::slimmingPaintV2Enabled())
             return true;
         break;
     case InPaintForSlimmingPaintV2:
@@ skipping 58 matching lines @@
 void DocumentLifecycle::ensureStateAtMost(State state)
 {
     ASSERT(state == VisualUpdatePending || state == StyleClean || state == LayoutClean);
     if (m_state <= state)
         return;
     ASSERT(canRewindTo(state));
     m_state = state;
 }
 
 }