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

src/effects/SkPerlinNoiseShader.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDither.h"
 #include "SkPerlinNoiseShader.h"
 #include "SkFlattenableBuffers.h"
@@ skipping 731 matching lines @@
 /////////////////////////////////////////////////////////////////////
 
 void GrGLSimplexNoise::emitCode(GrGLShaderBuilder* builder,
                                 const GrDrawEffect&,
                                 EffectKey key,
                                 const char* outputColor,
                                 const char* inputColor,
                                 const TextureSamplerArray&) {
     sk_ignore_unused_variable(inputColor);
 
-    const char* vCoords;
+    SkString vCoords;
     fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &vCoords);
 
     fSeedUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                    kFloat_GrSLType, "seed");
     const char* seedUni = builder->getUniformCStr(fSeedUni);
     fInvMatrixUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                         kMat33f_GrSLType, "invMatrix");
     const char* invMatrixUni = builder->getUniformCStr(fInvMatrixUni);
     fBaseFrequencyUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                             kVec2f_GrSLType, "baseFrequency");
@@ skipping 134 matching lines @@
     const char* yOffsets    = "yOffsets";
     const char* channel     = "channel";
 
     // Fill with some prime numbers
     builder->fsCodeAppendf("\t\tconst vec4 %s = vec4(13.0, 53.0, 101.0, 151.0);\n", xOffsets);
     builder->fsCodeAppendf("\t\tconst vec4 %s = vec4(109.0, 167.0, 23.0, 67.0);\n", yOffsets);
 
     // There are rounding errors if the floor operation is not performed here
     builder->fsCodeAppendf(
         "\t\tvec3 %s = vec3(floor((%s*vec3(%s, 1.0)).xy) * vec2(0.66) * %s, 0.0);\n",
-        noiseVecIni, invMatrixUni, vCoords, baseFrequencyUni);
+        noiseVecIni, invMatrixUni, vCoords.c_str(), baseFrequencyUni);
 
     // Perturb the texcoords with three components of noise
     builder->fsCodeAppendf("\t\t%s += 0.1 * vec3(%s(%s + vec3(  0.0,   0.0, %s)),"
                                                 "%s(%s + vec3( 43.0,  17.0, %s)),"
                                                 "%s(%s + vec3(-17.0, -43.0, %s)));\n",
                            noiseVecIni, noiseFuncName.c_str(), noiseVecIni, seedUni,
                                         noiseFuncName.c_str(), noiseVecIni, seedUni,
                                         noiseFuncName.c_str(), noiseVecIni, seedUni);
 
     builder->fsCodeAppendf("\t\t%s = vec4(0.0);\n", outputColor);
@@ skipping 40 matching lines @@
 }
 
 void GrGLPerlinNoise::emitCode(GrGLShaderBuilder* builder,
                                const GrDrawEffect&,
                                EffectKey key,
                                const char* outputColor,
                                const char* inputColor,
                                const TextureSamplerArray& samplers) {
     sk_ignore_unused_variable(inputColor);
 
-    const char* vCoords;
+    SkString vCoords;
     fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &vCoords);
 
     fInvMatrixUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                         kMat33f_GrSLType, "invMatrix");
     const char* invMatrixUni = builder->getUniformCStr(fInvMatrixUni);
     fBaseFrequencyUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                             kVec2f_GrSLType, "baseFrequency");
     const char* baseFrequencyUni = builder->getUniformCStr(fBaseFrequencyUni);
     fAlphaUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                     kFloat_GrSLType, "alpha");
@@ skipping 162 matching lines @@
                               "perlinnoise", SK_ARRAY_COUNT(gPerlinNoiseStitchArgs),
                               gPerlinNoiseStitchArgs, noiseCode.c_str(), &noiseFuncName);
     } else {
         builder->emitFunction(GrGLShaderBuilder::kFragment_ShaderType, kFloat_GrSLType,
                               "perlinnoise", SK_ARRAY_COUNT(gPerlinNoiseArgs),
                               gPerlinNoiseArgs, noiseCode.c_str(), &noiseFuncName);
     }
 
     // There are rounding errors if the floor operation is not performed here
     builder->fsCodeAppendf("\n\t\tvec2 %s = floor((%s * vec3(%s, 1.0)).xy) * %s;",
-                           noiseVec, invMatrixUni, vCoords, baseFrequencyUni);
+                           noiseVec, invMatrixUni, vCoords.c_str(), baseFrequencyUni);
 
     // Clear the color accumulator
     builder->fsCodeAppendf("\n\t\t%s = vec4(0.0);", outputColor);
 
     if (fStitchTiles) {
         // Set up TurbulenceInitial stitch values.
         builder->fsCodeAppendf("\n\t\tvec2 %s = %s;", stitchData, stitchDataUni);
     }
 
     builder->fsCodeAppendf("\n\t\tfloat %s = 1.0;", ratio);
@@ skipping 207 matching lines @@
     str->append(" seed: ");
     str->appendScalar(fSeed);
     str->append(" stitch tiles: ");
     str->append(fStitchTiles ? "true " : "false ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif