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

src/effects/SkMorphologyImageFilter.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 "SkMorphologyImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 306 matching lines @@
     fRadius = m.radius();
     fType = m.type();
 }
 
 void GrGLMorphologyEffect::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");
 
     const char* func;
     switch (fType) {
         case GrMorphologyEffect::kErode_MorphologyType:
             builder->fsCodeAppendf("\t\t%s = vec4(1, 1, 1, 1);\n", outputColor);
             func = "min";
             break;
         case GrMorphologyEffect::kDilate_MorphologyType:
             builder->fsCodeAppendf("\t\t%s = vec4(0, 0, 0, 0);\n", outputColor);
             func = "max";
             break;
         default:
             GrCrash("Unexpected type");
             func = ""; // suppress warning
             break;
     }
     const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
 
-    builder->fsCodeAppendf("\t\tvec2 coord = %s - %d.0 * %s;\n", coords, fRadius, imgInc);
+    builder->fsCodeAppendf("\t\tvec2 coord = %s - %d.0 * %s;\n", coords.c_str(), fRadius, imgInc);
     builder->fsCodeAppendf("\t\tfor (int i = 0; i < %d; i++) {\n", this->width());
     builder->fsCodeAppendf("\t\t\t%s = %s(%s, ", outputColor, func, outputColor);
     builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType, samplers[0], "coord");
     builder->fsCodeAppend(");\n");
     builder->fsCodeAppendf("\t\t\tcoord += %s;\n", imgInc);
     builder->fsCodeAppend("\t\t}\n");
     SkString modulate;
     GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
     builder->fsCodeAppend(modulate.c_str());
 }
@@ skipping 163 matching lines @@
     }
     GrTexture* input = inputBM.getTexture();
     SkIRect bounds;
     src.getBounds(&bounds);
     SkAutoTUnref<GrTexture> resultTex(apply_morphology(input, bounds,
         GrMorphologyEffect::kErode_MorphologyType, radius()));
     return SkImageFilterUtils::WrapTexture(resultTex, src.width(), src.height(), result);
 }
 
 #endif