Removed ScrollingCoordinator and a bunch of composited scrolling'

sky/engine/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 "config.h"
 #include "platform/graphics/CompositingReasons.h"
 
 #include "wtf/StdLibExtras.h"
 
 namespace blink {
@@ skipping 100 matching lines @@
         "Is the root layer" },
     { CompositingReasonLayerForAncestorClip,
         "layerForAncestorClip",
         "Secondary layer, applies a clip due to a sibling in the compositing tree" },
     { CompositingReasonLayerForDescendantClip,
         "layerForDescendantClip",
         "Secondary layer, to clip descendants of the owning layer" },
     { CompositingReasonLayerForPerspective,
         "layerForPerspective",
         "Secondary layer, to house the perspective transform for all descendants" },
-    { CompositingReasonLayerForHorizontalScrollbar,
-        "layerForHorizontalScrollbar",
-        "Secondary layer, the horizontal scrollbar layer" },
-    { CompositingReasonLayerForVerticalScrollbar,
-        "layerForVerticalScrollbar",
-        "Secondary layer, the vertical scrollbar layer" },
     { CompositingReasonLayerForOverflowControlsHost,
         "layerForOverflowControlsHost",
         "Secondary layer, the overflow controls host layer" },
-    { CompositingReasonLayerForScrollingContents,
-        "layerForScrollingContents",
-        "Secondary layer, to house contents that can be scrolled" },
-    { CompositingReasonLayerForScrollingContainer,
-        "layerForScrollingContainer",
-        "Secondary layer, used to position the scolling contents while scrolling" },
     { CompositingReasonLayerForSquashingContents,
         "layerForSquashingContents",
         "Secondary layer, home for a group of squashable content" },
     { CompositingReasonLayerForSquashingContainer,
         "layerForSquashingContainer",
         "Secondary layer, no-op layer to place the squashing layer correctly in the composited layer tree" },
     { CompositingReasonLayerForForeground,
         "layerForForeground",
         "Secondary layer, to contain any normal flow and positive z-index contents on top of a negative z-index layer" },
     { CompositingReasonLayerForBackground,
         "layerForBackground",
         "Secondary layer, to contain acceleratable background content" },
     { CompositingReasonLayerForMask,
         "layerForMask",
         "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" },
 };
 
 size_t kNumberOfCompositingReasons = WTF_ARRAY_LENGTH(kCompositingReasonStringMap);
 
 } // namespace blink