[Mac] Fix suspicious lifetime issue in KeystoneGlue.

The |brandFile_| ivar is stored and referenced in different methods, but
no memory management is applied. This object is likely resulting in
zombie crashes.

Bug: 847755
Change-Id: If0ae22356422b59b6537a09924f4d1a73b230d3e
Reviewed-on: https://chromium-review.googlesource.com/1081008
Reviewed-by: Elly Fong-Jones <[email protected]>
Commit-Queue: Robert Sesek <[email protected]>
Cr-Commit-Position: refs/heads/master@{#563325}
diff --git a/chrome/browser/mac/keystone_glue.h b/chrome/browser/mac/keystone_glue.h
index 830037c..c54b7dd 100644
--- a/chrome/browser/mac/keystone_glue.h
+++ b/chrome/browser/mac/keystone_glue.h
@@ -74,7 +74,8 @@
   NSString* url_;
   NSString* version_;
   std::string channel_;  // Logically: dev, beta, or stable.
-  NSString* brandFile_;  // Cached location of the brand file.
+  // Cached location of the brand file.
+  base::scoped_nsobject<NSString> brandFile_;
 
   // And the Keystone registration itself, with the active timer
   KSRegistration* registration_;  // strong