add context override of GeometryBufferMapThreshold

gyp/gpu.gypi

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 # Include this gypi to include all 'gpu' files
 # The parent gyp/gypi file must define
 #       'skia_src_path'     e.g. skia/trunk/src
 #       'skia_include_path' e.g. skia/trunk/include
 #
 # The skia build defines these in common_variables.gypi
@@ skipping 22 matching lines @@
       '<(skia_include_path)/gpu/GrRect.h',
       '<(skia_include_path)/gpu/GrRenderTarget.h',
       '<(skia_include_path)/gpu/GrResourceKey.h',
       '<(skia_include_path)/gpu/GrSurface.h',
       '<(skia_include_path)/gpu/GrShaderVar.h',
       '<(skia_include_path)/gpu/GrTexture.h',
       '<(skia_include_path)/gpu/GrTextureProvider.h',
       '<(skia_include_path)/gpu/GrTextureAccess.h',
       '<(skia_include_path)/gpu/GrTestUtils.h',
       '<(skia_include_path)/gpu/GrTypes.h',
-      '<(skia_include_path)/gpu/GrUserConfig.h',
       '<(skia_include_path)/gpu/GrXferProcessor.h',
 
       '<(skia_include_path)/gpu/effects/GrConstColorProcessor.h',
       '<(skia_include_path)/gpu/effects/GrCoverageSetOpXP.h',
       '<(skia_include_path)/gpu/effects/GrCustomXfermode.h',
       '<(skia_include_path)/gpu/effects/GrPorterDuffXferProcessor.h',
 
       '<(skia_include_path)/gpu/gl/GrGLConfig.h',
       '<(skia_include_path)/gpu/gl/GrGLExtensions.h',
       '<(skia_include_path)/gpu/gl/GrGLFunctions.h',
@@ skipping 366 matching lines @@
       '<(skia_src_path)/gpu/gl/debug/SkDebugGLContext.cpp',
       '<(skia_src_path)/gpu/gl/debug/SkDebugGLContext.h',
     ],
     'skgpu_null_gl_sources': [
       '<(skia_src_path)/gpu/gl/GrGLCreateNullInterface.cpp',
       '<(skia_src_path)/gpu/gl/SkNullGLContext.cpp',
       '<(skia_include_path)/gpu/gl/SkNullGLContext.h',
     ],
   },
 }