Use an SVGElementProxy in ReferenceClipPathOperation

third_party/WebKit/Source/core/style/BUILD.gn

 # Copyright 2016 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("//third_party/WebKit/Source/core/core.gni")
 
 blink_core_sources("rendering") {
   visibility = [ "//third_party/WebKit/Source/core/*" ]
 
   sources = [
     "AppliedTextDecoration.cpp",
     "BasicShapes.cpp",
     "BorderEdge.cpp",
     "BorderEdge.h",
     "BorderImageLength.h",
     "BorderImageLengthBox.h",
     "CachedUAStyle.h",
+    "ClipPathOperation.cpp",
     "ClipPathOperation.h",
     "ComputedStyle.cpp",
     "ComputedStyle.h",
     "ContentData.cpp",
     "CounterDirectives.cpp",
     "DataEquivalency.h",
     "DataPersistent.h",
     "DataRef.h",
     "FillLayer.cpp",
     "FilterOperation.cpp",
@@ skipping 55 matching lines @@
 blink_core_sources("svg") {
   sources = [
     "SVGComputedStyle.cpp",
     "SVGComputedStyleDefs.cpp",
   ]
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }