Fix case where GrGLEffectMatrix gives back a dangling ptr for the coords var name.

src/gpu/effects/GrConfigConversionEffect.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrConfigConversionEffect.h"
 #include "GrContext.h"
 #include "GrTBackendEffectFactory.h"
@@ skipping 12 matching lines @@
         fSwapRedAndBlue = effect.swapsRedAndBlue();
         fPMConversion = effect.pmConversion();
     }
 
     virtual void emitCode(GrGLShaderBuilder* builder,
                           const GrDrawEffect&,
                           EffectKey key,
                           const char* outputColor,
                           const char* inputColor,
                           const TextureSamplerArray& samplers) SK_OVERRIDE {
-        const char* coords;
+        SkString coords;
         GrSLType coordsType = fEffectMatrix.emitCode(builder, key, &coords);
         builder->fsCodeAppendf("\t\t%s = ", outputColor);
         builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType,
                                      samplers[0],
-                                     coords,
+                                     coords.c_str(),
                                      coordsType);
         builder->fsCodeAppend(";\n");
         if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
             SkASSERT(fSwapRedAndBlue);
             builder->fsCodeAppendf("\t%s = %s.bgra;\n", outputColor, outputColor);
         } else {
             const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
             switch (fPMConversion) {
                 case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
                     builder->fsCodeAppendf(
@@ skipping 238 matching lines @@
             // The PM conversions assume colors are 0..255
             return NULL;
         }
         AutoEffectUnref effect(SkNEW_ARGS(GrConfigConversionEffect, (texture,
                                                                      swapRedAndBlue,
                                                                      pmConversion,
                                                                      matrix)));
         return CreateEffectRef(effect);
     }
 }