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/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",
+    "AppliedTextDecoration.h",
     "BasicShapes.cpp",
+    "BasicShapes.h",
     "BorderEdge.cpp",
     "BorderEdge.h",
     "BorderImageLength.h",
     "BorderImageLengthBox.h",
     "CachedUAStyle.h",
     "ClipPathOperation.cpp",
     "ClipPathOperation.h",
     "ComputedStyle.cpp",
     "ComputedStyle.h",
     "ContentData.cpp",
+    "ContentData.h",
     "CounterDirectives.cpp",
+    "CounterDirectives.h",
     "DataEquivalency.h",
     "DataPersistent.h",
     "DataRef.h",
     "FillLayer.cpp",
+    "FillLayer.h",
     "FilterOperation.cpp",
     "FilterOperation.h",
     "FilterOperations.cpp",
     "FilterOperations.h",
     "GridArea.h",
     "GridPositionsResolver.cpp",
     "GridPositionsResolver.h",
     "NinePieceImage.cpp",
+    "NinePieceImage.h",
     "QuotesData.cpp",
     "QuotesData.h",
     "ShadowData.cpp",
     "ShadowData.h",
     "ShadowList.cpp",
     "ShadowList.h",
     "StyleBackgroundData.cpp",
+    "StyleBackgroundData.h",
     "StyleBoxData.cpp",
+    "StyleBoxData.h",
     "StyleContentAlignmentData.h",
     "StyleDeprecatedFlexibleBoxData.cpp",
+    "StyleDeprecatedFlexibleBoxData.h",
     "StyleFetchedImage.cpp",
+    "StyleFetchedImage.h",
     "StyleFetchedImageSet.cpp",
+    "StyleFetchedImageSet.h",
     "StyleFilterData.cpp",
+    "StyleFilterData.h",
     "StyleFlexibleBoxData.cpp",
+    "StyleFlexibleBoxData.h",
     "StyleGeneratedImage.cpp",
+    "StyleGeneratedImage.h",
     "StyleGridData.cpp",
+    "StyleGridData.h",
     "StyleGridItemData.cpp",
+    "StyleGridItemData.h",
     "StyleImage.cpp",
+    "StyleImage.h",
     "StyleInheritedData.cpp",
+    "StyleInheritedData.h",
     "StyleInheritedVariables.cpp",
     "StyleInheritedVariables.h",
     "StyleInvalidImage.h",
     "StyleMotionData.cpp",
     "StyleMotionData.h",
     "StyleMultiColData.cpp",
+    "StyleMultiColData.h",
     "StyleNonInheritedVariables.cpp",
     "StyleNonInheritedVariables.h",
     "StyleOffsetRotation.h",
     "StylePath.cpp",
     "StylePath.h",
     "StylePendingImage.h",
     "StyleRareInheritedData.cpp",
+    "StyleRareInheritedData.h",
     "StyleRareNonInheritedData.cpp",
+    "StyleRareNonInheritedData.h",
     "StyleScrollSnapData.cpp",
     "StyleScrollSnapData.h",
     "StyleSelfAlignmentData.h",
     "StyleSurroundData.cpp",
+    "StyleSurroundData.h",
     "StyleTransformData.cpp",
+    "StyleTransformData.h",
     "StyleVisualData.cpp",
+    "StyleVisualData.h",
     "StyleWillChangeData.cpp",
+    "StyleWillChangeData.h",
     "TextSizeAdjust.h",
   ]
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }
 
 blink_core_sources("svg") {
   sources = [
     "SVGComputedStyle.cpp",
+    "SVGComputedStyle.h",
     "SVGComputedStyleDefs.cpp",
+    "SVGComputedStyleDefs.h",
   ]
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }