Create xfer processor backend.

src/gpu/gl/GrGpuGL.h

Index: src/gpu/gl/GrGpuGL.h
diff --git a/src/gpu/gl/GrGpuGL.h b/src/gpu/gl/GrGpuGL.h
index 8a609884e155014c53e2358da12d1d48e9e70647..76995b921d70e659ef3e8ffaaf16ef070001cf9e 100644
--- a/src/gpu/gl/GrGpuGL.h
+++ b/src/gpu/gl/GrGpuGL.h
@@ -172,11 +172,7 @@ private:
                        size_t* indexOffsetInBytes);
 
     // Subclasses should call this to flush the blend state.
-    // The params should be the final coefficients to apply
-    // (after any blending optimizations or dual source blending considerations
-    // have been accounted for).
-    void flushBlend(const GrOptDrawState& optState, bool isLines,
-                    GrBlendCoeff srcCoeff, GrBlendCoeff dstCoeff);
+    void flushBlend(const GrOptDrawState& optState);
 
     bool hasExtension(const char* ext) const { return fGLContext.hasExtension(ext); }