Initialize destinations variables before calling GL functions...

chrome/gpu/gpu_info_collector_mac.mm

Index: chrome/gpu/gpu_info_collector_mac.mm
===================================================================
--- chrome/gpu/gpu_info_collector_mac.mm	(revision 68425)
+++ chrome/gpu/gpu_info_collector_mac.mm	(working copy)
@@ -81,13 +81,15 @@
   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);
   }