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

src/effects/SkLightingImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLightingImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 1186 matching lines @@
 GrGLLightingEffect::~GrGLLightingEffect() {
     delete fLight;
 }
 
 void GrGLLightingEffect::emitCode(GrGLShaderBuilder* builder,
                                   const GrDrawEffect&,
                                   EffectKey key,
                                   const char* outputColor,
                                   const char* inputColor,
                                   const TextureSamplerArray& samplers) {
-    const char* coords;
+    SkString coords;
     fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &coords);
 
     fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                               kVec2f_GrSLType,
                                              "ImageIncrement");
     fSurfaceScaleUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                            kFloat_GrSLType,
                                            "SurfaceScale");
     fLight->emitLightColorUniform(builder);
     SkString lightFunc;
@@ skipping 42 matching lines @@
                                 sobelFuncName.c_str());
     SkString interiorNormalName;
     builder->emitFunction(GrGLShaderBuilder::kFragment_ShaderType,
                           kVec3f_GrSLType,
                           "interiorNormal",
                           SK_ARRAY_COUNT(gInteriorNormalArgs),
                           gInteriorNormalArgs,
                           interiorNormalBody.c_str(),
                           &interiorNormalName);
 
-    builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords);
+    builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords.c_str());
     builder->fsCodeAppend("\t\tfloat m[9];\n");
 
     const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
     const char* surfScale = builder->getUniformCStr(fSurfaceScaleUni);
 
     int index = 0;
     for (int dy = -1; dy <= 1; dy++) {
         for (int dx = -1; dx <= 1; dx++) {
             SkString texCoords;
             texCoords.appendf("coord + vec2(%d, %d) * %s", dx, dy, imgInc);
@@ skipping 291 matching lines @@
 
 #endif
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDiffuseLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSpecularLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDistantLight)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkPointLight)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSpotLight)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END