Fix the bug that negative outline-offset is covered up by composited

third_party/WebKit/Source/platform/graphics/CompositingReasons.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 "platform/graphics/CompositingReasons.h"
 
 #include "wtf/StdLibExtras.h"
 
 namespace blink {
 
@@ skipping 116 matching lines @@
      "Secondary layer, to contain the mask contents"},
     {CompositingReasonLayerForClippingMask, "layerForClippingMask",
      "Secondary layer, for clipping mask"},
     {CompositingReasonLayerForScrollingBlockSelection,
      "layerForScrollingBlockSelection",
      "Secondary layer, to house block selection gaps for composited scrolling "
      "with no scrolling contents"},
     {CompositingReasonInlineTransform, "inlineTransform",
      "Has an inline transform, which causes subsequent layers to assume "
      "overlap"},
+    {CompositingReasonLayerForDecoration, "layerForDecoration",
+     "Layer painted on top of other layers as decoration"},
 };
 
 const size_t kNumberOfCompositingReasons =
     WTF_ARRAY_LENGTH(kCompositingReasonStringMap);
 
 }  // namespace blink