Add missing .h files to .gn files that have a .cc file next to it in the gn file already.

third_party/WebKit/Source/core/layout/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") {
   sources = [
     "LayoutSVGBlock.cpp",
     "LayoutSVGBlock.h",
@@ skipping 57 matching lines @@
     "LayoutSVGViewportContainer.h",
     "SVGCharacterData.h",
     "SVGLayoutSupport.cpp",
     "SVGLayoutSupport.h",
     "SVGLayoutTreeAsText.cpp",
     "SVGLayoutTreeAsText.h",
     "SVGMarkerData.h",
     "SVGResources.cpp",
     "SVGResources.h",
     "SVGResourcesCache.cpp",
+    "SVGResourcesCache.h",
     "SVGResourcesCycleSolver.cpp",
     "SVGResourcesCycleSolver.h",
     "SVGTextChunkBuilder.cpp",
     "SVGTextChunkBuilder.h",
     "SVGTextFragment.h",
     "SVGTextLayoutAttributesBuilder.cpp",
     "SVGTextLayoutAttributesBuilder.h",
     "SVGTextLayoutEngine.cpp",
     "SVGTextLayoutEngine.h",
     "SVGTextLayoutEngineBaseline.cpp",
     "SVGTextLayoutEngineBaseline.h",
     "SVGTextLayoutEngineSpacing.cpp",
     "SVGTextLayoutEngineSpacing.h",
     "SVGTextMetrics.cpp",
     "SVGTextMetrics.h",
     "SVGTextQuery.cpp",
     "SVGTextQuery.h",
   ]
 
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }