stop using SkXfermode -- use SkBlendMode instead

skia/config/SkUserConfig.h

 /*
  * Copyright (C) 2006 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
@@ skipping 198 matching lines @@
 // pending Skia ripmap support.
 // (https://bugs.chromium.org/p/skia/issues/detail?id=4863)
 #ifndef    SK_SUPPORT_LEGACY_ANISOTROPIC_MIPMAP_SCALE
 #   define SK_SUPPORT_LEGACY_ANISOTROPIC_MIPMAP_SCALE
 #endif
 
 #ifndef    SK_IGNORE_ETC1_SUPPORT
 #   define SK_IGNORE_ETC1_SUPPORT
 #endif
 
-#ifndef    SK_SUPPORT_LEGACY_XFERMODE_IS_PUBLIC
-#   define SK_SUPPORT_LEGACY_XFERMODE_IS_PUBLIC
-#endif
-
 #ifndef    SK_IGNORE_GPU_DITHER
 #   define SK_IGNORE_GPU_DITHER
 #endif
 
 #ifndef    SK_SUPPORT_LEGACY_EVAL_CUBIC
 #   define SK_SUPPORT_LEGACY_EVAL_CUBIC
 #endif
 
 ///////////////////////// Imported from BUILD.gn and skia_common.gypi
 
@@ skipping 28 matching lines @@
 // Enabling the screenspace AA tessellating path renderer needs rebaselines.
 #define SK_DISABLE_SCREENSPACE_TESS_AA_PATH_RENDERER
 
 // Disable analytic AA until we fix all the Chrome tests.
 // (we now set analytic AA as default in Skia.)
 #define SK_NO_ANALYTIC_AA
 
 // ===== End Chrome-specific definitions =====
 
 #endif