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

src/effects/SkDisplacementMapEffect.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 "SkDisplacementMapEffect.h"
 #include "SkFlattenableBuffers.h"
 #include "SkUnPreMultiply.h"
@@ skipping 395 matching lines @@
                                          EffectKey key,
                                          const char* outputColor,
                                          const char* inputColor,
                                          const TextureSamplerArray& samplers) {
     sk_ignore_unused_variable(inputColor);
 
     fScaleUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                     kVec2f_GrSLType, "Scale");
     const char* scaleUni = builder->getUniformCStr(fScaleUni);
 
-    const char* dCoordsIn;
+    SkString dCoordsIn;
     GrSLType dCoordsType = fDisplacementEffectMatrix.emitCode(
                                 builder, key, &dCoordsIn, NULL, "DISPL");
-    const char* cCoordsIn;
+    SkString cCoordsIn;
     GrSLType cCoordsType = fColorEffectMatrix.emitCode(
                                 builder, key, &cCoordsIn, NULL, "COLOR");
 
     const char* dColor = "dColor";
     const char* cCoords = "cCoords";
     const char* outOfBounds = "outOfBounds";
     const char* nearZero = "1e-6"; // Since 6.10352e−5 is the smallest half float, use
                                    // a number smaller than that to approximate 0, but
                                    // leave room for 32-bit float GPU rounding errors.
 
     builder->fsCodeAppendf("\t\tvec4 %s = ", dColor);
     builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType,
                                  samplers[0],
-                                 dCoordsIn,
+                                 dCoordsIn.c_str(),
                                  dCoordsType);
     builder->fsCodeAppend(";\n");
 
     // Unpremultiply the displacement
     builder->fsCodeAppendf("\t\t%s.rgb = (%s.a < %s) ? vec3(0.0) : clamp(%s.rgb / %s.a, 0.0, 1.0);",
                            dColor, dColor, nearZero, dColor, dColor);
 
     builder->fsCodeAppendf("\t\tvec2 %s = %s + %s*(%s.",
-                           cCoords, cCoordsIn, scaleUni, dColor);
+                           cCoords, cCoordsIn.c_str(), scaleUni, dColor);
 
     switch (fXChannelSelector) {
       case SkDisplacementMapEffect::kR_ChannelSelectorType:
         builder->fsCodeAppend("r");
         break;
       case SkDisplacementMapEffect::kG_ChannelSelectorType:
         builder->fsCodeAppend("g");
         break;
       case SkDisplacementMapEffect::kB_ChannelSelectorType:
         builder->fsCodeAppend("b");
@@ skipping 79 matching lines @@
                                                   colorTex);
 
     colorKey <<= GrGLEffectMatrix::kKeyBits;
     EffectKey xKey = displacementMap.xChannelSelector() << (2 * GrGLEffectMatrix::kKeyBits);
     EffectKey yKey = displacementMap.yChannelSelector() << (2 * GrGLEffectMatrix::kKeyBits +
                                                             SkDisplacementMapEffect::kKeyBits);
 
     return xKey | yKey | displKey | colorKey;
 }
 #endif