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

src/core/SkXfermode.cpp

 
 /*
  * Copyright 2006 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 "SkXfermode.h"
@@ skipping 930 matching lines @@
         virtual void emitCode(GrGLShaderBuilder* builder,
                               const GrDrawEffect& drawEffect,
                               EffectKey key,
                               const char* outputColor,
                               const char* inputColor,
                               const TextureSamplerArray& samplers) SK_OVERRIDE {
             SkXfermode::Mode mode = drawEffect.castEffect<XferEffect>().mode();
             const GrTexture* backgroundTex = drawEffect.castEffect<XferEffect>().backgroundAccess().getTexture();
             const char* dstColor;
             if (backgroundTex) {
-                const char* bgCoords;
+                SkString bgCoords;
                 GrSLType bgCoordsType = fBackgroundEffectMatrix.emitCode(builder, key, &bgCoords, NULL, "BG");
                 dstColor = "bgColor";
                 builder->fsCodeAppendf("\t\tvec4 %s = ", dstColor);
                 builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType,
                                              samplers[0],
-                                             bgCoords,
+                                             bgCoords.c_str(),
                                              bgCoordsType);
                 builder->fsCodeAppendf(";\n");
             } else {
                 dstColor = builder->dstColor();
             }
             SkASSERT(NULL != dstColor);
 
             // We don't try to optimize for this case at all
             if (NULL == inputColor) {
                 builder->fsCodeAppendf("\t\tconst vec4 ones = %s;\n", GrGLSLOnesVecf(4));
@@ skipping 1003 matching lines @@
     return proc16;
 }
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkProcCoeffXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkClearXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSrcXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDstInXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDstOutXfermode)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END