fix up GrGLProgrambuilder precision on varyings

src/gpu/gl/builders/GrGLProgramBuilder.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 GrGLProgramBuilder_DEFINED
 #define GrGLProgramBuilder_DEFINED
 
@@ skipping 129 matching lines @@
 class GrGLGPBuilder : public virtual GrGLUniformBuilder {
 public:
     /*
      * addVarying allows fine grained control for setting up varyings between stages.  If you just
      * need to take an attribute and pass it through to an output value in a fragment shader, use
      * addPassThroughAttribute.
      * TODO convert most uses of addVarying to addPassThroughAttribute
      */
     virtual void addVarying(const char* name,
                             GrGLVarying*,
-                            GrSLPrecision fsPrecision = kDefault_GrSLPrecision) = 0;
+                            GrSLPrecision precision = kDefault_GrSLPrecision) = 0;
 
     /*
      * This call can be used by GP to pass an attribute through all shaders directly to 'output' in
      * the fragment shader.  Though this call effects both the vertex shader and fragment shader,
      * it expects 'output' to be defined in the fragment shader before this call is made.
      * TODO it might be nicer behavior to have a flag to declare output inside this call
      */
     virtual void addPassThroughAttribute(const GrGeometryProcessor::Attribute*,
                                          const char* output) = 0;
 
@@ skipping 90 matching lines @@
     const GrGLContextInfo& ctxInfo() const override;
 
     GrGLGpu* gpu() const override { return fGpu; }
 
     GrGLXPFragmentBuilder* getFragmentShaderBuilder() override { return &fFS; }
     GrGLVertexBuilder* getVertexShaderBuilder() override { return &fVS; }
 
     void addVarying(
             const char* name,
             GrGLVarying*,
-            GrSLPrecision fsPrecision = kDefault_GrSLPrecision) override;
+            GrSLPrecision precision = kDefault_GrSLPrecision) override;
 
     void addPassThroughAttribute(const GrPrimitiveProcessor::Attribute*,
                                  const char* output) override;
 
     SeparableVaryingHandle addSeparableVarying(
         const char* name,
         GrGLVertToFrag*,
         GrSLPrecision fsPrecision = kDefault_GrSLPrecision) override;
 
     // Handles for program uniforms (other than per-effect uniforms)
@@ skipping 127 matching lines @@
     GrGLPrimitiveProcessor::TransformsOut fOutCoords;
     SkTArray<UniformHandle> fSamplerUniforms;
     SeparableVaryingInfoArray fSeparableVaryingInfos;
 
     friend class GrGLShaderBuilder;
     friend class GrGLVertexBuilder;
     friend class GrGLFragmentShaderBuilder;
     friend class GrGLGeometryBuilder;
 };
 #endif