Remove SK_PREFER_LEGACY_FLOAT_XFERMODES

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 259 matching lines @@
 #endif
 
 #ifndef    SK_SUPPORT_LEGACY_INT_COLORMATRIX
 #   define SK_SUPPORT_LEGACY_INT_COLORMATRIX
 #endif
 
 #ifndef    SK_LEGACY_STROKE_CURVES
 #   define SK_LEGACY_STROKE_CURVES
 #endif
 
-#ifndef    SK_PREFER_LEGACY_FLOAT_XFERMODES
-#   define SK_PREFER_LEGACY_FLOAT_XFERMODES
-#endif
-
 ///////////////////////// Imported from BUILD.gn and skia_common.gypi
 
 /* In some places Skia can use static initializers for global initialization,
  *  or fall back to lazy runtime initialization. Chrome always wants the latter.
  */
 #define SK_ALLOW_STATIC_GLOBAL_INITIALIZERS 0
 
 /* Forcing the unoptimized path for the offset image filter in skia until
  * all filters used in Blink support the optimized path properly
  */
 #define SK_DISABLE_OFFSETIMAGEFILTER_OPTIMIZATION
 
 /* This flag forces Skia not to use typographic metrics with GDI.
  */
 #define SK_GDI_ALWAYS_USE_TEXTMETRICS_FOR_FONT_METRICS
 
 #define IGNORE_ROT_AA_RECT_OPT
 #define SK_IGNORE_BLURRED_RRECT_OPT
 #define SK_USE_DISCARDABLE_SCALEDIMAGECACHE
 #define SK_WILL_NEVER_DRAW_PERSPECTIVE_TEXT
 
 #define SK_ATTR_DEPRECATED          SK_NOTHING_ARG1
 #define SK_ENABLE_INST_COUNT        0
 #define GR_GL_CUSTOM_SETUP_HEADER   "GrGLConfig_chrome.h"
 
 // ===== End Chrome-specific definitions =====
 
 #endif