Only update style-determined composited reasons during the chicken/egg compositing update

Source/core/rendering/compositing/CompositingReasonFinder.cpp

 // Copyright 2014 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.
 
 #include "config.h"
 #include "core/rendering/compositing/CompositingReasonFinder.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/page/Page.h"
@@ skipping 108 matching lines @@
 
 CompositingReasons CompositingReasonFinder::nonStyleDeterminedDirectReasons(const RenderLayer* layer) const
 {
     CompositingReasons directReasons = CompositingReasonNone;
     RenderObject* renderer = layer->renderer();
 
     if (hasOverflowScrollTrigger()) {
         // IsUnclippedDescendant is only actually stale during the chicken/egg code path.
         // FIXME: Use compositingInputs().isUnclippedDescendant to ASSERT that
         // this value isn't stale.
-        if (layer->potentiallyStaleIsUnclippedDescendant())
+        if (layer->compositingInputs().isUnclippedDescendant)
             directReasons |= CompositingReasonOutOfFlowClipping;
 
         if (layer->scrollParent())
             directReasons |= CompositingReasonOverflowScrollingParent;
 
         if (layer->needsCompositedScrolling())
             directReasons |= CompositingReasonOverflowScrollingTouch;
     }
 
     if (requiresCompositingForPositionFixed(renderer, layer, 0))
@@ skipping 87 matching lines @@
             if (viewportConstrainedNotCompositedReason)
                 *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForBoundsOutOfView;
             return false;
         }
     }
 
     return true;
 }
 
 }