Start moving signin code out of browser/sync.

chrome/browser/ui/webui/signin/login_ui_service.cc

Index: chrome/browser/ui/webui/signin/login_ui_service.cc
diff --git a/chrome/browser/ui/webui/signin/login_ui_service.cc b/chrome/browser/ui/webui/signin/login_ui_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6de85189516fa57ebc8b00a4e49f736c64c159aa
--- /dev/null
+++ b/chrome/browser/ui/webui/signin/login_ui_service.cc
@@ -0,0 +1,60 @@
+// Copyright (c) 2012 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.
+
+#include "chrome/browser/ui/webui/signin/login_ui_service.h"
+
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/browser_window.h"
+#include "chrome/common/url_constants.h"
+#include "content/browser/renderer_host/render_view_host.h"
+#include "content/public/browser/render_view_host_delegate.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_ui.h"
+
+LoginUIService::LoginUIService(Profile* profile)
+    : ui_(NULL),
+      profile_(profile) {
+}
+
+LoginUIService::~LoginUIService() {}
+
+void LoginUIService::SetLoginUI(content::WebUI* ui) {
+  DCHECK(!current_login_ui() || current_login_ui() == ui);
+  ui_ = ui;
+}
+
+void LoginUIService::ClearLoginUI(content::WebUI* ui) {
+  if (current_login_ui() == ui)

[James Hawkins, 2012/02/10 23:08:01]

What are the use cases for allowing |ui| to not match |current_login_ui()|?

[Andrew T Wilson (Slow), 2012/02/11 01:50:45]

The use cases are that you might have multiple sync setup handlers around (say,
a promo *and* a settings page). Or you might open settings in multiple windows,
etc. ClearLoginUI() is called defensively in some places as a catch-all (i.e. in
the destructor for SyncSetupHandler()) to make sure we don't accidentally leave
ourselves set as the current login UI (say, if the renderer crashes, or you hit
the back button, or close the tab, or whatever).

So the use case might be:

1) Bring up promo
2) Bring up settings but don't open the overlay.
3) Close settings. We call ClearLoginUI(), but we still want the promo to be
left as the current_login_ui.

+    ui_ = NULL;
+}
+
+void LoginUIService::FocusLoginUI() {
+  if (!ui_) {
+    NOTREACHED() << "FocusLoginUI() called with no active login UI";
+    return;
+  }
+  ui_->GetWebContents()->GetRenderViewHost()->delegate()->Activate();
+}
+
+void LoginUIService::ShowLoginUI() {
+  if (ui_) {
+    // We already have active login UI - make it visible.
+    FocusLoginUI();
+    return;
+  }
+
+  // Need to navigate to the settings page and display the UI.
+  if (profile_) {
+    Browser* browser = BrowserList::GetLastActiveWithProfile(profile_);
+    if (!browser) {
+      browser = Browser::Create(profile_);
+      browser->ShowOptionsTab(chrome::kSyncSetupSubPage);
+      browser->window()->Show();
+    } else {
+      browser->ShowOptionsTab(chrome::kSyncSetupSubPage);
+    }
+  }
+}