Implement texel buffers

src/gpu/glsl/GrGLSLShaderBuilder.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLSLShaderBuilder_DEFINED
 #define GrGLSLShaderBuilder_DEFINED
 
@@ skipping 129 matching lines @@
     void appendDecls(const VarArray& vars, SkString* out) const;
 
     /**
      * Features that should only be enabled internally by the builders.
      */
     enum GLSLPrivateFeature {
         kFragCoordConventions_GLSLPrivateFeature,
         kBlendEquationAdvanced_GLSLPrivateFeature,
         kBlendFuncExtended_GLSLPrivateFeature,
         kExternalTexture_GLSLPrivateFeature,
+        kTexelBuffer_GLSLPrivateFeature,
         kFramebufferFetch_GLSLPrivateFeature,
         kNoPerspectiveInterpolation_GLSLPrivateFeature,
         kSampleVariables_GLSLPrivateFeature,
         kSampleMaskOverrideCoverage_GLSLPrivateFeature,
         kLastGLSLPrivateFeature = kSampleMaskOverrideCoverage_GLSLPrivateFeature
     };
 
     /*
      * A general function which enables an extension in a shader if the feature bit is not present
      *
@@ skipping 73 matching lines @@
     int fCodeIndex;
     bool fFinalized;
 
     friend class GrGLSLProgramBuilder;
     friend class GrGLProgramBuilder;
     friend class GrGLSLVaryingHandler; // to access noperspective interpolation feature.
     friend class GrGLPathProgramBuilder; // to access fInputs.
     friend class GrVkPipelineStateBuilder;
 };
 #endif