Removed ScrollingCoordinator and a bunch of composited scrolling'

sky/engine/platform/graphics/CompositingReasons.cpp

Index: sky/engine/platform/graphics/CompositingReasons.cpp
diff --git a/sky/engine/platform/graphics/CompositingReasons.cpp b/sky/engine/platform/graphics/CompositingReasons.cpp
index 881df6c484ccc9fa09f40869356c63712405e713..8f5321decd6c3f2af5f506e6a3d06c0d2620aadd 100644
--- a/sky/engine/platform/graphics/CompositingReasons.cpp
+++ b/sky/engine/platform/graphics/CompositingReasons.cpp
@@ -118,21 +118,9 @@ const CompositingReasonStringMap kCompositingReasonStringMap[] = {
     { 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" },
@@ -151,9 +139,6 @@ const CompositingReasonStringMap kCompositingReasonStringMap[] = {
     { 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" },