Add appendPrecisionModifier method to GrGLSLShaderBuilder

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 75 matching lines @@
        va_start(args, format);
        this->code().prependVAList(format, args);
        va_end(args);
     }
 
     /**
      * Appends a variable declaration to one of the shaders
      */
     void declAppend(const GrGLSLShaderVar& var);
 
+    /**
+     * Appends a precision qualifier followed by a space, if relevant for the GLSL version.
+     */
+    void appendPrecisionModifier(GrSLPrecision);
+
     /** Emits a helper function outside of main() in the fragment shader. */
     void emitFunction(GrSLType returnType,
                       const char* name,
                       int argCnt,
                       const GrGLSLShaderVar* args,
                       const char* body,
                       SkString* outName);
 
     /*
      * Combines the various parts of the shader to create a single finalized shader string.
@@ skipping 114 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