Add a CHECK to investigate crash in OAuth2ManifestHandler::Parse

extensions/common/manifest_handlers/oauth2_manifest_handler.cc

Index: extensions/common/manifest_handlers/oauth2_manifest_handler.cc
diff --git a/extensions/common/manifest_handlers/oauth2_manifest_handler.cc b/extensions/common/manifest_handlers/oauth2_manifest_handler.cc
index 1d32ecb09fd87cb785dcb8a244d33ad136903792..3bcf95880c6357300b53a39d99e6a6878a32e623 100644
--- a/extensions/common/manifest_handlers/oauth2_manifest_handler.cc
+++ b/extensions/common/manifest_handlers/oauth2_manifest_handler.cc
@@ -53,6 +53,10 @@ bool OAuth2ManifestHandler::Parse(Extension* extension,
     return false;
   }
 
+  // This should not be possible, but it looks like the source of the crash in
+  // http://crbug.com/445683. Perhaps something is overwriting the stack.
+  CHECK(info);
+
   // HasPath checks for whether the manifest is allowed to have
   // oauth2.auto_approve based on whitelist, and if it is present.
   // GetBoolean reads the value of auto_approve directly from dict to prevent