Create xfer processor backend.

src/gpu/GrGeometryProcessor.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGeometryProcessor_DEFINED
 #define GrGeometryProcessor_DEFINED
 
@@ skipping 44 matching lines @@
         : fVertexStride(0)
         , fColor(color)
         , fCoverage(coverage)
         , fWillUseGeoShader(false)
         , fHasVertexColor(false)
         , fHasVertexCoverage(false)
         , fHasLocalCoords(false) {}
 
     virtual const char* name() const = 0;
 
-    /** Implemented using GLProcessor::GenKey as described in this class's comment. */
+    /**
+     * Sets a unique key on the GrProcessorKeyBuilder that is directly associated with this geometry
+     * processor's GL backend implementation.
+     */
     virtual void getGLProcessorKey(const GrBatchTracker& bt,
                                    const GrGLCaps& caps,
                                    GrProcessorKeyBuilder* b) const = 0;
 
 
     /** Returns a new instance of the appropriate *GL* implementation class
         for the given GrProcessor; caller is responsible for deleting
         the object. */
     virtual GrGLGeometryProcessor* createGLInstance(const GrBatchTracker& bt) const = 0;
 
@@ skipping 92 matching lines @@
     GrColor fColor;
     uint8_t fCoverage;
     bool fWillUseGeoShader;
     bool fHasVertexColor;
     bool fHasVertexCoverage;
     bool fHasLocalCoords;
 
     typedef GrProcessor INHERITED;
 };
 #endif