Make XPFragmentBuilder only Builder with access to DstCopy.

src/gpu/gl/builders/GrGLFragmentShaderBuilder.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 GrGLFragmentShaderBuilder_DEFINED
 #define GrGLFragmentShaderBuilder_DEFINED
 
 #include "GrGLShaderBuilder.h"
 
 class GrGLVarying;
 
 /*
  * This base class encapsulates the functionality which the GP uses to build fragment shaders
  */
-class GrGLGPFragmentBuilder : public GrGLShaderBuilder {
+class GrGLFragmentBuilder : public GrGLShaderBuilder {
 public:
-    GrGLGPFragmentBuilder(GrGLProgramBuilder* program) : INHERITED(program) {}
-    virtual ~GrGLGPFragmentBuilder() {}
+    GrGLFragmentBuilder(GrGLProgramBuilder* program) : INHERITED(program) {}
+    virtual ~GrGLFragmentBuilder() {}
     /**
      * Use of these features may require a GLSL extension to be enabled. Shaders may not compile
      * if code is added that uses one of these features without calling enableFeature()
      */
     enum GLSLFeature {
         kStandardDerivatives_GLSLFeature = 0,
         kLastGLSLFeature = kStandardDerivatives_GLSLFeature
     };
 
     /**
@@ skipping 19 matching lines @@
     friend class GrGLPathProcessor;
 
     typedef GrGLShaderBuilder INHERITED;
 };
 
 /*
  * Fragment processor's, in addition to all of the above, may need to use dst color so they use
  * this builder to create their shader.  Because this is the only shader builder the FP sees, we
  * just call it FPShaderBuilder
  */
-class GrGLFPFragmentBuilder : public GrGLGPFragmentBuilder {
+class GrGLXPFragmentBuilder : public GrGLFragmentBuilder {
 public:
-    GrGLFPFragmentBuilder(GrGLProgramBuilder* program) : INHERITED(program) {}
+    GrGLXPFragmentBuilder(GrGLProgramBuilder* program) : INHERITED(program) {}
 
     /** Returns the variable name that holds the color of the destination pixel. This may be NULL if
         no effect advertised that it will read the destination. */
     virtual const char* dstColor() = 0;
 
 private:
-    typedef GrGLGPFragmentBuilder INHERITED;
+    typedef GrGLFragmentBuilder INHERITED;
 };
 
 // TODO rename to Fragment Builder
-class GrGLFragmentShaderBuilder : public GrGLFPFragmentBuilder {
+class GrGLFragmentShaderBuilder : public GrGLXPFragmentBuilder {
 public:
     typedef uint8_t DstReadKey;
     typedef uint8_t FragPosKey;
 
     /**  Returns a key for adding code to read the copy-of-dst color in service of effects that
         require reading the dst. It must not return 0 because 0 indicates that there is no dst
         copy read at all (in which case this function should not be called). */
     static DstReadKey KeyForDstRead(const GrTexture* dstCopy, const GrGLCaps&);
 
     /** Returns a key for reading the fragment location. This should only be called if there is an
@@ skipping 64 matching lines @@
     bool fTopLeftFragPosRead;
     int  fCustomColorOutputIndex;
 
     // some state to verify shaders and effects are consistent, this is reset between effects by
     // the program creator
     bool fHasReadDstColor;
     bool fHasReadFragmentPosition;
 
     friend class GrGLProgramBuilder;
 
-    typedef GrGLFPFragmentBuilder INHERITED;
+    typedef GrGLXPFragmentBuilder INHERITED;
 };
 
 #endif