Fix fb variable name in GLSL

src/gpu/glsl/GrGLSLFragmentShaderBuilder.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 "GrGLSLFragmentShaderBuilder.h"
 #include "GrRenderTarget.h"
 #include "GrRenderTargetPriv.h"
@@ skipping 248 matching lines @@
                          glslCaps->fbFetchExtensionString());
 
         // Some versions of this extension string require declaring custom color output on ES 3.0+
         const char* fbFetchColorName = glslCaps->fbFetchColorName();
         if (glslCaps->fbFetchNeedsCustomOutput()) {
             this->enableCustomOutput();
             fOutputs[fCustomColorOutputIndex].setTypeModifier(GrShaderVar::kInOut_TypeModifier);
             fbFetchColorName = DeclaredColorOutputName();
             // Set the dstColor to an intermediate variable so we don't override it with the output
             this->codeAppendf("vec4 %s = %s;", kDstColorName, fbFetchColorName);
+        } else {
+            return fbFetchColorName;
         }
     }
     return kDstColorName;
 }
 
 void GrGLSLFragmentShaderBuilder::enableAdvancedBlendEquationIfNeeded(GrBlendEquation equation) {
     SkASSERT(GrBlendEquationIsAdvanced(equation));
 
     const GrGLSLCaps& caps = *fProgramBuilder->glslCaps();
     if (!caps.mustEnableAdvBlendEqs()) {
@@ skipping 110 matching lines @@
     fMangleString.appendf("_c%d", fSubstageIndices[fSubstageIndices.count() - 2]);
 }
 
 void GrGLSLFragmentShaderBuilder::onAfterChildProcEmitCode() {
     SkASSERT(fSubstageIndices.count() >= 2);
     fSubstageIndices.pop_back();
     fSubstageIndices.back()++;
     int removeAt = fMangleString.findLastOf('_');
     fMangleString.remove(removeAt, fMangleString.size() - removeAt);
 }