The login dialog was being opened with the main browser window as a parent in...

chrome/browser/sync/profile_sync_service.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifdef CHROME_PERSONALIZATION
 
 #ifndef CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 
 #include <string>
@@ skipping 45 matching lines @@
   // - Credentials are now in flight for authentication.
   virtual void OnStateChanged() = 0;
  protected:
   virtual ~ProfileSyncServiceObserver() { }
 };
 
 // ProfileSyncService is the layer between browser subsystems like bookmarks,
 // and the sync backend.
 class ProfileSyncService : public NotificationObserver,
                            public browser_sync::SyncFrontend,
-                           public browser_sync::UnrecoverableErrorHandler {
+                           public browser_sync::UnrecoverableErrorHandler,
+                           public SyncSetupWizard::WizardParentDelegate {
  public:
   typedef ProfileSyncServiceObserver Observer;
   typedef browser_sync::SyncBackendHost::Status Status;
 
   enum SyncEventCodes  {
     MIN_SYNC_EVENT_CODE = 0,
 
     // Events starting the sync service.
     START_FROM_NTP = 1,      // Sync was started from the ad in NTP
     START_FROM_WRENCH = 2,   // Sync was started from the Wrench menu.
@@ skipping 16 matching lines @@
   };
 
   explicit ProfileSyncService(Profile* profile);
   virtual ~ProfileSyncService();
 
   // Initializes the object. This should be called every time an object of this
   // class is constructed.
   void Initialize();
 
   // Enables/disables sync for user.
-  virtual void EnableForUser();
+  virtual void EnableForUser(gfx::NativeWindow parent_window);

[tim (not reviewing), 2009/10/29 21:58:44]

can we call it setup_dialog_parent_window, and add a comment above like 
"Enables/disables sync for the user. This will cause a setup dialog to be shown,
and you may use |setup_dialog_parent_window| to parent this dialog from a window
of your choosing."

   virtual void DisableForUser();
 
   // Whether sync is enabled by user or not.
   bool HasSyncSetupCompleted() const;
   void SetSyncSetupCompleted();
 
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
@@ skipping 26 matching lines @@
   // Returns false if a dialog is already showing, an auth attempt is in
   // progress, the sync system is already authenticated, or some error
   // occurred preventing the action. We make it the duty of ProfileSyncService
   // to open the dialog to easily ensure only one is ever showing.
   bool SetupInProgress() const {
     return !HasSyncSetupCompleted() && WizardIsVisible();
   }
   bool WizardIsVisible() const {
     return wizard_.IsVisible();
   }
-  void ShowLoginDialog();
+  gfx::NativeWindow GetWizardParent() const {

[tim (not reviewing), 2009/10/29 21:58:44]

please add virtual

+    return wizard_parent_window_;
+  }
+  void ShowLoginDialog(gfx::NativeWindow parent_window);

[tim (not reviewing), 2009/10/29 21:58:44]

the name of the variable is fine here, but please add a comment explaining it.

 
   // Pretty-printed strings for a given StatusSummary.
   static std::wstring BuildSyncStatusSummaryText(
       const browser_sync::SyncBackendHost::StatusSummary& summary);
 
   // Returns true if the SyncBackendHost has told us it's ready to accept
   // changes.
   // TODO(timsteele): What happens if the bookmark model is loaded, a change
   // takes place, and the backend isn't initialized yet?
   bool sync_initialized() const { return backend_initialized_; }
@@ skipping 133 matching lines @@
   // one, it is actually an error and this bool isn't needed.
   bool expecting_first_run_auth_needed_event_;
 
   // Various pieces of UI query this value to determine if they should show
   // an "Authenticating.." type of message.  We are the only central place
   // all auth attempts funnel through, so it makes sense to provide this.
   // As its name suggests, this should NOT be used for anything other than UI.
   bool is_auth_in_progress_;
 
   SyncSetupWizard wizard_;
+  gfx::NativeWindow wizard_parent_window_;
 
   // True if an unrecoverable error (e.g. violation of an assumed invariant)
   // occurred during syncer operation.  This value should be checked before
   // doing any work that might corrupt things further.
   bool unrecoverable_error_detected_;
 
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncService);
 };
 
 #endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 
 #endif  // CHROME_PERSONALIZATION