Remove more scrolling code from Sky

sky/engine/platform/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//sky/engine/build/scripts/scripts.gni")
 import("//sky/engine/config.gni")
 import("//testing/test.gni")
 
 # Most targets in this file are private actions so use that as the default.
@@ skipping 462 matching lines @@
     "PlatformExport.h",
     "PlatformScreen.cpp",
     "PlatformScreen.h",
     "PlatformThreadData.cpp",
     "PlatformThreadData.h",
     "PurgeableVector.cpp",
     "PurgeableVector.h",
     "RefCountedSupplement.h",
     "ScriptForbiddenScope.cpp",
     "ScriptForbiddenScope.h",
-    "scroll/ScrollTypes.h",
     "SharedBuffer.cpp",
     "SharedBuffer.h",
     "SharedBufferChunkReader.cpp",
     "SharedBufferChunkReader.h",
     "SharedTimer.cpp",
     "SharedTimer.h",
     "Supplementable.h",
     "text/BidiCharacterRun.cpp",
     "text/BidiCharacterRun.h",
     "text/BidiContext.cpp",
@@ skipping 246 matching lines @@
     # See https://bugs.webkit.org/show_bug.cgi?id=62916.
     # TODO(GYP)
     #'cflags': ['-marm'],
     #    'conditions': [
     #      ['OS=="android"', {
     #        'cflags!': ['-mthumb'],
     #      }],
     #    ],
   }
 }