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

src/effects/SkBicubicImageFilter.cpp

 /*
  * Copyright 2013 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 "SkBicubicImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 206 matching lines @@
     : INHERITED(factory)
     , fEffectMatrix(drawEffect.castEffect<GrBicubicEffect>().coordsType()) {
 }
 
 void GrGLBicubicEffect::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);
     fCoefficientsUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                            kMat44f_GrSLType, "Coefficients");
     fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                              kVec2f_GrSLType, "ImageIncrement");
 
     const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
     const char* coeff = builder->getUniformCStr(fCoefficientsUni);
 
     SkString cubicBlendName;
 
     static const GrGLShaderVar gCubicBlendArgs[] = {
         GrGLShaderVar("coefficients",  kMat44f_GrSLType),
         GrGLShaderVar("t",             kFloat_GrSLType),
         GrGLShaderVar("c0",            kVec4f_GrSLType),
         GrGLShaderVar("c1",            kVec4f_GrSLType),
         GrGLShaderVar("c2",            kVec4f_GrSLType),
         GrGLShaderVar("c3",            kVec4f_GrSLType),
     };
     builder->emitFunction(GrGLShaderBuilder::kFragment_ShaderType,
                           kVec4f_GrSLType,
                           "cubicBlend",
                           SK_ARRAY_COUNT(gCubicBlendArgs),
                           gCubicBlendArgs,
                           "\tvec4 ts = vec4(1.0, t, t * t, t * t * t);\n"
                           "\tvec4 c = coefficients * ts;\n"
                           "\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
                           &cubicBlendName);
-    builder->fsCodeAppendf("\tvec2 coord = %s - %s * vec2(0.5, 0.5);\n", coords, imgInc);
+    builder->fsCodeAppendf("\tvec2 coord = %s - %s * vec2(0.5, 0.5);\n", coords.c_str(), imgInc);
     builder->fsCodeAppendf("\tvec2 f = fract(coord / %s);\n", imgInc);
     for (int y = 0; y < 4; ++y) {
         for (int x = 0; x < 4; ++x) {
             SkString coord;
             coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
             builder->fsCodeAppendf("\tvec4 s%d%d = ", x, y);
             builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType,
                                          samplers[0],
                                          coord.c_str());
             builder->fsCodeAppend(";\n");
@@ skipping 99 matching lines @@
     GrPaint paint;
     paint.addColorEffect(GrBicubicEffect::Create(srcTexture, fCoefficients))->unref();
     SkRect srcRect;
     srcBM.getBounds(&srcRect);
     context->drawRectToRect(paint, dstRect, srcRect);
     return SkImageFilterUtils::WrapTexture(dst, desc.fWidth, desc.fHeight, result);
 }
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////