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

src/gpu/gl/GrGLEffectMatrix.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLEffectMatrix.h"
 #include "GrDrawEffect.h"
 #include "GrTexture.h"
@@ skipping 27 matching lines @@
     } else if (SkMatrix::kTranslate_Mask & combinedTypes) {
         key |= kTrans_MatrixType;
     } else {
         key |= kIdentity_MatrixType;
     }
     return key;
 }
 
 GrSLType GrGLEffectMatrix::emitCode(GrGLShaderBuilder* builder,
                                     EffectKey key,
-                                    const char** fsCoordName,
-                                    const char** vsCoordName,
+                                    SkString* fsCoordName,
+                                    SkString* vsCoordName,
                                     const char* suffix) {
     GrSLType varyingType = kVoid_GrSLType;
     const char* uniName;
     key &= kKeyMask;
     switch (key & kMatrixTypeKeyMask) {
         case kIdentity_MatrixType:
             fUniType = kVoid_GrSLType;
             varyingType = kVec2f_GrSLType;
             break;
         case kTrans_MatrixType:
@@ skipping 85 matching lines @@
     }
     return varyingType;
 }
 
 /**
     * This is similar to emitCode except that it performs perspective division in the FS if the
     * texture coordinates have a w coordinate. The fsCoordName always refers to a vec2f.
     */
 void GrGLEffectMatrix::emitCodeMakeFSCoords2D(GrGLShaderBuilder* builder,
                                               EffectKey key,
-                                              const char** fsCoordName,
-                                              const char** vsVaryingName,
+                                              SkString* fsCoordName,
+                                              SkString* vsVaryingName,
                                               GrSLType* vsVaryingType,
                                               const char* suffix) {
-    const char* fsVaryingName;
+    SkString fsVaryingName;
 
     GrSLType varyingType = this->emitCode(builder,
                                           key,
                                           &fsVaryingName,
                                           vsVaryingName,
                                           suffix);
     if (kVec3f_GrSLType == varyingType) {
 
         const char* coordName = "coords2D";
         SkString suffixedCoordName;
         if (NULL != suffix) {
             suffixedCoordName.append(coordName);
             suffixedCoordName.append(suffix);
             coordName = suffixedCoordName.c_str();
         }
         builder->fsCodeAppendf("\tvec2 %s = %s.xy / %s.z;",
-                               coordName, fsVaryingName, fsVaryingName);
+                               coordName, fsVaryingName.c_str(), fsVaryingName.c_str());
         if (NULL != fsCoordName) {
             *fsCoordName = coordName;
         }
     } else if(NULL != fsCoordName) {
         *fsCoordName = fsVaryingName;
     }
     if (NULL != vsVaryingType) {
         *vsVaryingType = varyingType;
     }
 }
@@ skipping 41 matching lines @@
             if (!fPrevMatrix.cheapEqualTo(combined)) {
                 uniformManager.setSkMatrix(fUni, combined);
                 fPrevMatrix = combined;
             }
             break;
         }
         default:
             GrCrash("Unexpected uniform type.");
     }
 }