Fix crash when switching to a profile that cannot be opened

chrome/browser/profiles/profile_manager.h

Index: chrome/browser/profiles/profile_manager.h
diff --git a/chrome/browser/profiles/profile_manager.h b/chrome/browser/profiles/profile_manager.h
index e3e742c9995536c5defdc4a8f7001d3872563c56..bb16e059f21d2d2b688dd3a299af90a47fdac312 100644
--- a/chrome/browser/profiles/profile_manager.h
+++ b/chrome/browser/profiles/profile_manager.h
@@ -401,6 +401,10 @@ class ProfileManager : public base::NonThreadSafe,
   typedef std::map<base::FilePath, linked_ptr<ProfileInfo> > ProfilesInfoMap;
   ProfilesInfoMap profiles_info_;
 
+  // Owns profiles that fails initialization. Like normal profiles, they are not

[Peter Kasting, 2016/06/13 04:43:20]

Nit: fail

[WC Leung, 2016/06/13 08:06:45]

Acknowledged.

[WC Leung, 2016/06/15 13:08:39]

Done.

+  // safe to destroy from memory before shutdown.

[Peter Kasting, 2016/06/13 04:43:20]

Nit: "...they must not be deleted before shutdown."

But it would be nice to explain why, since it's not obvious why a failed profile
can't just be deleted.

[WC Leung, 2016/06/13 08:06:45]

Acknowledged.

[WC Leung, 2016/06/15 13:08:39]

Actually some services (e.g. pref store) that Profile is depending on appears to
be creating async tasks that outlives itself. My syzyasan report points to
JSONPrefStore. BTW, I'd rather not having this written in the source code.

Unfortunately I do not have enough understanding of the pref store as a whole,
so I cannot fix it myself.

+  std::vector<std::unique_ptr<Profile>> failed_profiles_;
+
   // Manages the process of creating, deleteing and updating Desktop shortcuts.
   std::unique_ptr<ProfileShortcutManager> profile_shortcut_manager_;