dom-ui sync: Eliminate jank when customizing sync settings.

chrome/browser/sync/profile_sync_service.h

Index: chrome/browser/sync/profile_sync_service.h
===================================================================
--- chrome/browser/sync/profile_sync_service.h	(revision 84869)
+++ chrome/browser/sync/profile_sync_service.h	(working copy)
@@ -38,6 +38,7 @@
 class Profile;
 class ProfileSyncFactory;
 class SigninManager;
+class WebUI;
 
 namespace browser_sync {
 class BackendMigrator;
@@ -239,18 +240,26 @@
   bool WizardIsVisible() const {
     return wizard_.IsVisible();
   }
-  virtual void ShowLoginDialog();
+
   SyncSetupWizard& get_wizard() { return wizard_; }
 
+  // Shows the login screen of the Sync setup wizard.  |web_ui| is the WebUI
+  // object for a current settings tab, NULL if one doesn't exist or the calling
+  // code doesn't know.
+  virtual void ShowLoginDialog(WebUI* web_ui);
+
   // This method handles clicks on "sync error" UI, showing the appropriate
-  // dialog for the error condition (relogin / enter passphrase).
-  virtual void ShowErrorUI();
+  // dialog for the error condition (relogin / enter passphrase).  |web_ui| is
+  // the WebUI object for a current settings tab, NULL if one doesn't exist or
+  // the calling code doesn't know.
+  virtual void ShowErrorUI(WebUI* web_ui);
 
   // Shows the configure screen of the Sync setup wizard. If |sync_everything|
   // is true, shows the corresponding page in the customize screen; otherwise,
   // displays the page that gives the user the ability to select which data
-  // types to sync.
-  void ShowConfigure(bool sync_everything);
+  // types to sync.  |web_ui| is the WebUI object for a current settings tab,
+  // NULL if one doesn't exist or the calling code doesn't know.
+  void ShowConfigure(WebUI* web_ui, bool sync_everything);
 
   void PromptForExistingPassphrase();