Swizzle shader output and blend when using GL_RED to implement kAlpha_8_GrPixelConfig

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 157 matching lines @@
       '<(skia_src_path)/gpu/GrTraceMarker.cpp',
       '<(skia_src_path)/gpu/GrTraceMarker.h',
       '<(skia_src_path)/gpu/GrTracing.h',
       '<(skia_src_path)/gpu/GrTestUtils.cpp',
       '<(skia_src_path)/gpu/GrSWMaskHelper.cpp',
       '<(skia_src_path)/gpu/GrSWMaskHelper.h',
       '<(skia_src_path)/gpu/GrSoftwarePathRenderer.cpp',
       '<(skia_src_path)/gpu/GrSoftwarePathRenderer.h',
       '<(skia_src_path)/gpu/GrSurfacePriv.h',
       '<(skia_src_path)/gpu/GrSurface.cpp',
+      '<(skia_src_path)/gpu/GrSwizzle.h',
       '<(skia_src_path)/gpu/GrTexture.cpp',
       '<(skia_src_path)/gpu/GrTextureParamsAdjuster.h',
       '<(skia_src_path)/gpu/GrTextureParamsAdjuster.cpp',
       '<(skia_src_path)/gpu/GrTextureProvider.cpp',
       '<(skia_src_path)/gpu/GrTexturePriv.h',
       '<(skia_src_path)/gpu/GrTextureAccess.cpp',
       '<(skia_src_path)/gpu/GrTransferBuffer.h',
       '<(skia_src_path)/gpu/GrTRecorder.h',
       '<(skia_src_path)/gpu/GrVertexBuffer.h',
       '<(skia_src_path)/gpu/GrVertices.h',
@@ skipping 299 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',
     ],
   },
 }