Implement texel buffers

include/gpu/GrFragmentProcessor.h

Index: include/gpu/GrFragmentProcessor.h
diff --git a/include/gpu/GrFragmentProcessor.h b/include/gpu/GrFragmentProcessor.h
index 55b2f905d9c52e8ebf6adb08b43f2dd81b77eef4..c3f291cc5f53e510a1f43de582f0018745aaf7ee 100644
--- a/include/gpu/GrFragmentProcessor.h
+++ b/include/gpu/GrFragmentProcessor.h
@@ -59,6 +59,7 @@ public:
         : INHERITED()
         , fUsesLocalCoords(false)
         , fNumTexturesExclChildren(0)
+        , fNumBuffersExclChildren(0)
         , fNumTransformsExclChildren(0) {}
 
     ~GrFragmentProcessor() override;
@@ -74,6 +75,8 @@ public:
 
     int numTexturesExclChildren() const { return fNumTexturesExclChildren; }
 
+    int numBuffersExclChildren() const { return fNumBuffersExclChildren; }
+
     int numTransformsExclChildren() const { return fNumTransformsExclChildren; }
 
     int numTransforms() const { return fCoordTransforms.count(); }
@@ -122,6 +125,7 @@ public:
 
 protected:
     void addTextureAccess(const GrTextureAccess* textureAccess) override;
+    void addBufferAccess(const GrBufferAccess*) override;
 
     /**
      * Fragment Processor subclasses call this from their constructor to register coordinate
@@ -210,6 +214,7 @@ private:
      */
     SkSTArray<4, const GrCoordTransform*, true>     fCoordTransforms;
     int                                             fNumTexturesExclChildren;
+    int                                             fNumBuffersExclChildren;
     int                                             fNumTransformsExclChildren;
     SkSTArray<1, const GrFragmentProcessor*, true>  fChildProcessors;