Use vertexless shaders when NVpr is available

src/gpu/gl/GrGLShaderBuilder.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLShaderBuilder_DEFINED
 #define GrGLShaderBuilder_DEFINED
 
@@ skipping 432 matching lines @@
     SkSTArray<10, AttributePair, true>  fEffectAttributes;
 
     GrGLUniformManager::UniformHandle   fViewMatrixUniform;
 
     GrGLShaderVar*                      fPositionVar;
     GrGLShaderVar*                      fLocalCoordsVar;
 
     typedef GrGLShaderBuilder INHERITED;
 };
 
+////////////////////////////////////////////////////////////////////////////////
+
+class GrGLFragmentOnlyShaderBuilder : public GrGLShaderBuilder {
+public:
+    GrGLFragmentOnlyShaderBuilder(GrGpuGL*, GrGLUniformManager&, const GrGLProgramDesc&);
+
+    int getNumTexCoordSets() const { return fNumTexCoordSets; }
+    int addTexCoordSets(int count) { return (fNumTexCoordSets += count) - count; }
+
+    virtual GrGLProgramEffects* createAndEmitEffects(
+                const GrEffectStage* effectStages[],
+                const EffectKey effectKeys[],
+                int effectCnt,
+                SkString* inOutFSColor,
+                GrSLConstantVec* fsInOutColorKnownValue) SK_OVERRIDE;
+
+private:
+    int fNumTexCoordSets;
+
+    typedef GrGLShaderBuilder INHERITED;
+};
+
 #endif