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

src/effects/SkMatrixConvolutionImageFilter.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 "SkMatrixConvolutionImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 367 matching lines @@
     }
     builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType, sampler, coord);
 }
 
 void GrGLMatrixConvolutionEffect::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");
     fKernelUni = builder->addUniformArray(GrGLShaderBuilder::kFragment_ShaderType,
                                              kFloat_GrSLType, "Kernel", fKernelSize.width() * fKernelSize.height());
     fTargetUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                              kVec2f_GrSLType, "Target");
     fGainUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                    kFloat_GrSLType, "Gain");
     fBiasUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                    kFloat_GrSLType, "Bias");
 
     const char* target = builder->getUniformCStr(fTargetUni);
     const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
     const char* kernel = builder->getUniformCStr(fKernelUni);
     const char* gain = builder->getUniformCStr(fGainUni);
     const char* bias = builder->getUniformCStr(fBiasUni);
     int kWidth = fKernelSize.width();
     int kHeight = fKernelSize.height();
 
     builder->fsCodeAppend("\t\tvec4 sum = vec4(0, 0, 0, 0);\n");
-    builder->fsCodeAppendf("\t\tvec2 coord = %s - %s * %s;\n", coords, target, imgInc);
+    builder->fsCodeAppendf("\t\tvec2 coord = %s - %s * %s;\n", coords.c_str(), target, imgInc);
     builder->fsCodeAppendf("\t\tfor (int y = 0; y < %d; y++) {\n", kHeight);
     builder->fsCodeAppendf("\t\t\tfor (int x = 0; x < %d; x++) {\n", kWidth);
     builder->fsCodeAppendf("\t\t\t\tfloat k = %s[y * %d + x];\n", kernel, kWidth);
     builder->fsCodeAppendf("\t\t\t\tvec2 coord2 = coord + vec2(x, y) * %s;\n", imgInc);
     builder->fsCodeAppend("\t\t\t\tvec4 c = ");
     appendTextureLookup(builder, samplers[0], "coord2", fTileMode);
     builder->fsCodeAppend(";\n");
     if (!fConvolveAlpha) {
         builder->fsCodeAppend("\t\t\t\tc.rgb /= c.a;\n");
     }
     builder->fsCodeAppend("\t\t\t\tsum += c * k;\n");
     builder->fsCodeAppend("\t\t\t}\n");
     builder->fsCodeAppend("\t\t}\n");
     if (fConvolveAlpha) {
         builder->fsCodeAppendf("\t\t%s = sum * %s + %s;\n", outputColor, gain, bias);
         builder->fsCodeAppendf("\t\t%s.rgb = clamp(%s.rgb, 0.0, %s.a);\n", outputColor, outputColor, outputColor);
     } else {
         builder->fsCodeAppend("\t\tvec4 c = ");
-        appendTextureLookup(builder, samplers[0], coords, fTileMode);
+        appendTextureLookup(builder, samplers[0], coords.c_str(), fTileMode);
         builder->fsCodeAppend(";\n");
         builder->fsCodeAppendf("\t\t%s.a = c.a;\n", outputColor);
         builder->fsCodeAppendf("\t\t%s.rgb = sum.rgb * %s + %s;\n", outputColor, gain, bias);
         builder->fsCodeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
     }
 }
 
 namespace {
 
 int encodeXY(int x, int y) {
@@ skipping 133 matching lines @@
                                                 fBias,
                                                 fTarget,
                                                 fTileMode,
                                                 fConvolveAlpha);
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #endif