Make safe browsing's last download finder's SearchInProfile idempotent.

Different orderings of notifications could previously trip up the finder.
They don't now.

BUG=397229
R=shess@chromium.org

Review URL: https://codereview.chromium.org/418103006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@285495 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/safe_browsing/last_download_finder.cc

@@ -145,6 +145,14 @@ void LastDownloadFinder::SearchInProfile(Profile* profile) {
     return;
   }
 
+  // Exit early if already processing this profile. This could happen if, for
+  // example, NOTIFICATION_PROFILE_ADDED arrives after construction while
+  // waiting for NOTIFICATION_HISTORY_LOADED.
+  if (std::find(profiles_.begin(), profiles_.end(), profile) !=
+      profiles_.end()) {
+    return;
+  }
+
   HistoryService* history_service =
       HistoryServiceFactory::GetForProfile(profile, Profile::IMPLICIT_ACCESS);
   // No history service is returned for profiles that do not save history.