Initialize destinations variables before calling GL functions...

chrome/gpu/gpu_info_collector_mac.mm

 // Copyright (c) 2006-2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/gpu/gpu_info_collector.h"
 #include "base/logging.h"
 #include "base/scoped_ptr.h"
 #include "base/string_piece.h"
 #include "base/sys_string_conversions.h"
 #include "app/gfx/gl/gl_bindings.h"
@@ skipping 63 matching lines @@
   return s_found;
 }
 
 // Gets the numeric HLSL version.
 // You pass it the current GL major version, to give it a hint where to look.
 static int GetShaderNumericVersion(int gl_major_version) {
   int gl_hlsl_major = 0, gl_hlsl_minor = 0;
   int shader_version = 0;
 
   if (gl_major_version == 1) {
-    char *gl_extensions_string = (char*)glGetString(GL_EXTENSIONS);
-    if (strstr(gl_extensions_string, "GL_ARB_shading_language_100")) {
+    const char *gl_extensions_string = (const char*)glGetString(GL_EXTENSIONS);
+    if (gl_extensions_string &&
+        strstr(gl_extensions_string, "GL_ARB_shading_language_100")) {
       gl_hlsl_major = 1;
       gl_hlsl_minor = 0;
     }
   } else if (gl_major_version > 1) {
-    char *glsl_version_string = (char*)glGetString(GL_SHADING_LANGUAGE_VERSION);
+    const char *glsl_version_string =
+        (const char*)glGetString(GL_SHADING_LANGUAGE_VERSION);
     if (glsl_version_string)
       sscanf(glsl_version_string, "%u.%u", &gl_hlsl_major, &gl_hlsl_minor);
   }
 
   shader_version = (gl_hlsl_major << 8) | (gl_hlsl_minor & 0xFF);
   return shader_version;
 }
 
 
 static std::wstring CStringToWString(const char *s) {
@@ skipping 61 matching lines @@
                             shader_version,
                             gl_version,
                             false);
 
   gpu_info->SetProgress(GPUInfo::kComplete);
 
   return true;
 }
 
 }  // namespace gpu_info_collector