add native draw bitmap with alpha mask

core/fxge/include/cfx_fxgedevice.h

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_FXGE_INCLUDE_CFX_FXGEDEVICE_H_
 #define CORE_FXGE_INCLUDE_CFX_FXGEDEVICE_H_
 
 #include "core/fxge/include/cfx_renderdevice.h"
@@ skipping 10 matching lines @@
               bool bRgbByteOrder,
               CFX_DIBitmap* pOriDevice,
               bool bGroupKnockout);
   bool Create(int width,
               int height,
               FXDIB_Format format,
               CFX_DIBitmap* pOriDevice);
 
 #ifdef _SKIA_SUPPORT_
   bool AttachRecorder(SkPictureRecorder* recorder);
+  void Clear(uint32_t color);
   SkPictureRecorder* CreateRecorder(int size_x, int size_y);
   void DebugVerifyBitmapIsPreMultiplied() const override;
+  bool SetBitsWithMask(const CFX_DIBSource* pBitmap,
+                       const CFX_DIBSource* pMask,
+                       int left,
+                       int top,
+                       int bitmap_alpha,
+                       int blend_type) override;
 #endif
 
  private:
   bool m_bOwnedBitmap;
 };
 
 #endif  // CORE_FXGE_INCLUDE_CFX_FXGEDEVICE_H_