More missing Skia includes

cc/paint/paint_flags.h

 // Copyright 2017 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.
 
 #ifndef CC_PAINT_PAINT_FLAGS_H_
 #define CC_PAINT_PAINT_FLAGS_H_
 
 #include "base/compiler_specific.h"
 #include "cc/paint/paint_export.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkDrawLooper.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
 #include "third_party/skia/include/core/SkMaskFilter.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkPathEffect.h"
+#include "third_party/skia/include/core/SkShader.h"
 #include "third_party/skia/include/core/SkTypeface.h"
 
 namespace cc {
 
 using PaintShader = SkShader;
 
 class CC_PAINT_EXPORT PaintFlags {
  public:
   enum Style {
     kFill_Style = SkPaint::kFill_Style,
@@ skipping 191 matching lines @@
   return flags.paint_;
 }
 
 ALWAYS_INLINE const SkPaint* ToSkPaint(const PaintFlags* flags) {
   return &flags->paint_;
 }
 
 }  // namespace cc
 
 #endif  // CC_PAINT_PAINT_FLAGS_H_