Fail to create GrContext when we get a NULL for a GL/GLSL version string

src/gpu/gl/GrGLExtensions.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 "gl/GrGLExtensions.h"
 #include "gl/GrGLDefines.h"
 #include "gl/GrGLUtil.h"
@@ skipping 36 matching lines @@
                           GrGLGetIntegervProc getIntegerv) {
     fInitialized = false;
     fStrings->reset();
 
     if (NULL == getString) {
         return false;
     }
 
     // glGetStringi and indexed extensions were added in version 3.0 of desktop GL and ES.
     const GrGLubyte* verString = getString(GR_GL_VERSION);
-    if (NULL == verString) {
+    GrGLVersion version = GrGLGetVersionFromString((const char*) verString);
+    if (GR_GL_INVALID_VER == version) {
         return false;
     }
-    GrGLVersion version = GrGLGetVersionFromString((const char*) verString);
+
     bool indexed = version >= GR_GL_VER(3, 0);
 
     if (indexed) {
         if (NULL == getStringi || NULL == getIntegerv) {
             return false;
         }
         GrGLint extensionCnt = 0;
         getIntegerv(GR_GL_NUM_EXTENSIONS, &extensionCnt);
         fStrings->push_back_n(extensionCnt);
         for (int i = 0; i < extensionCnt; ++i) {
@@ skipping 62 matching lines @@
 
 void GrGLExtensions::print(const char* sep) const {
     if (NULL == sep) {
         sep = " ";
     }
     int cnt = fStrings->count();
     for (int i = 0; i < cnt; ++i) {
         GrPrintf("%s%s", (*fStrings)[i].c_str(), (i < cnt - 1) ? sep : "");
     }
 }