SVG objects with same idrefs conflict when under different shadow root

third_party/WebKit/Source/core/svg/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("svg") {
   # Split into multiple static libraries on Windows official builds, where we
   # run into a 2GB max size limit.
   if (is_win && is_official_build) {
@@ skipping 249 matching lines @@
     "SVGTextPositioningElement.cpp",
     "SVGTextPositioningElement.h",
     "SVGTitleElement.cpp",
     "SVGTitleElement.h",
     "SVGTransform.cpp",
     "SVGTransformDistance.cpp",
     "SVGTransformDistance.h",
     "SVGTransformList.cpp",
     "SVGTransformListTearOff.cpp",
     "SVGTransformTearOff.cpp",
+    "SVGTreeScopeResources.cpp",
+    "SVGTreeScopeResources.h",
     "SVGURIReference.cpp",
     "SVGURIReference.h",
     "SVGUnitTypes.cpp",
     "SVGUnitTypes.h",
     "SVGUnknownElement.cpp",
     "SVGUnknownElement.h",
     "SVGUseElement.cpp",
     "SVGUseElement.h",
     "SVGViewElement.cpp",
     "SVGViewElement.h",
@@ skipping 17 matching lines @@
     "graphics/filters/SVGFilterBuilder.h",
     "properties/SVGAnimatedProperty.cpp",
     "properties/SVGPropertyTearOff.cpp",
   ]
 
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }