Bug 888784 - Get rid of FormHistory.shutdown. r=mak

FormHistory.shutdown was called via FormHistoryStartup.js's profile-before-change
observer to close the database synchronously.

Now FormHistory uses AsyncShutdown and closes the database asynchronously, so
FormHistory.shutdown is no longer required.

MozReview-Commit-ID: Lok5vx1dOTW

--HG--
extra : rebase_source : c368ab3895fd0c4f39d01d195578afdcf49a5f91

toolkit/components/satchel/FormHistory.jsm

@@ -1510,8 +1510,6 @@ this.FormHistory = {
       },
     });
   },
-
-  shutdown() { dbClose(true); },
 };
 
 // Prevent add-ons from redefining this API

toolkit/components/satchel/FormHistoryStartup.js

@@ -30,9 +30,6 @@ FormHistoryStartup.prototype = {
       case "formhistory-expire-now":
         FormHistory.expireOldEntries();
         break;
-      case "profile-before-change":
-        FormHistory.shutdown();
-        break;
       case "profile-after-change":
         this.init();
         break;
@@ -51,7 +48,6 @@ FormHistoryStartup.prototype = {
     Services.prefs.addObserver("browser.formfill.", this, true);
 
     // triggers needed service cleanup and db shutdown
-    Services.obs.addObserver(this, "profile-before-change", true);
     Services.obs.addObserver(this, "idle-daily", true);
     Services.obs.addObserver(this, "formhistory-expire-now", true);