fix up GrGLProgrambuilder precision on varyings

src/gpu/gl/builders/GrGLVertexShaderBuilder.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLVertexShaderBuilder.h"
 #include "GrGLProgramBuilder.h"
 #include "../GrGLGLSL.h"
 #include "../GrGLGpu.h"
 
 #define GL_CALL(X) GR_GL_CALL(fProgramBuilder->gpu()->glInterface(), X)
 #define GL_CALL_RET(R, X) GR_GL_CALL_RET(fProgramBuilder->gpu()->glInterface(), R, X)
 
 GrGLVertexBuilder::GrGLVertexBuilder(GrGLProgramBuilder* program)
     : INHERITED(program)
     , fRtAdjustName(nullptr) {
 }
 
-void GrGLVertexBuilder::addVarying(const char* name, GrGLVarying* v) {
+void GrGLVertexBuilder::addVarying(const char* name, GrSLPrecision precision, GrGLVarying* v) {
     fOutputs.push_back();
     fOutputs.back().setType(v->fType);
     fOutputs.back().setTypeModifier(GrGLShaderVar::kVaryingOut_TypeModifier);
+    fOutputs.back().setPrecision(precision);
     fProgramBuilder->nameVariable(fOutputs.back().accessName(), 'v', name);
     v->fVsOut = fOutputs.back().getName().c_str();
 }
 
 void GrGLVertexBuilder::emitAttributes(const GrGeometryProcessor& gp) {
     int vaCount = gp.numAttribs();
     for (int i = 0; i < vaCount; i++) {
         this->addAttribute(&gp.getAttrib(i));
     }
     return;
@@ skipping 64 matching lines @@
     for (int i = 0; i < fInputs.count(); ++i) {
         const GrGLShaderVar& attr = fInputs[i];
         // if attribute already added, don't add it again
         if (attr.getName().equals(var.getName())) {
             return false;
         }
     }
     fInputs.push_back(var);
     return true;
 }