Bug 539057 - better flow with start over [r=mconnor]

* Adds an option to the manage account to change sync option.
* Changes "start over" to "use a different account".
* Hides the "start over" button on the sync options page when not running through the whole process.
* Adds a prompt when starting over (which fixes bug 524186).

services/sync/locales/en-US/fx-prefs.dtd

@@ -88,6 +88,8 @@
 <!ENTITY recoverPassword.label        "Recover Password">
 <!ENTITY changePassphrase.label       "Change Secret Phrase">
 <!ENTITY resetPassphrase.label        "Reset Secret Phrase">
+<!ENTITY resetSync.label              "Reset Sync">
+<!ENTITY differentAccount.label       "Use a Different Account">
 <!ENTITY startOver.label              "Start Over">
 
 <!ENTITY syncPrefsCaption.label       "Browser Sync">

services/sync/locales/en-US/fx-prefs.properties

@@ -25,4 +25,8 @@ additionalClients.label = and %S additional devices
 
 bookmarkCount.label = %S bookmarks
 historyCount.label  = %S days of history
-passwordCount.label = %S passwords
+passwordCount.label = %S passwords
+
+differentAccount.title = Use a Different Account?
+differentAccount.label = This will reset all of your sync account information and preferences.
+differentAccountConfirm.label = Reset All Information

services/sync/modules/service.js

@@ -641,6 +641,18 @@ WeaveSvc.prototype = {
     return false;
   },
 
+  startOver: function() {
+    this.logout();
+    // Reset all engines
+    this.resetClient();
+    // Reset Weave prefs
+    Svc.Prefs.resetBranch("");
+    // Find weave logins and remove them.
+    Svc.Login.findLogins({}, PWDMGR_HOST, "", "").map(function(login) {
+      Svc.Login.removeLogin(login);
+    });
+  },
+
   _autoConnect: let (attempts = 0) function _autoConnect() {
     let reason = "";
     if (this._mpLocked())