Add a SigninAllowed policy.

chrome/browser/ui/browser_command_controller.cc

Index: chrome/browser/ui/browser_command_controller.cc
diff --git a/chrome/browser/ui/browser_command_controller.cc b/chrome/browser/ui/browser_command_controller.cc
index 546d80dc43c5cfe40bd5e513c92bbf90cee04e1f..1aa3bac716f422c07d26d49dc43e432191a1ce15 100644
--- a/chrome/browser/ui/browser_command_controller.cc
+++ b/chrome/browser/ui/browser_command_controller.cc
@@ -16,6 +16,8 @@
 #include "chrome/browser/sessions/tab_restore_service.h"
 #include "chrome/browser/sessions/tab_restore_service_factory.h"
 #include "chrome/browser/shell_integration.h"
+#include "chrome/browser/signin/signin_manager.h"
+#include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/browser/ui/bookmarks/bookmark_tab_helper.h"
@@ -210,9 +212,20 @@ BrowserCommandController::BrowserCommandController(
     tab_restore_service->AddObserver(this);
     TabRestoreServiceChanged(tab_restore_service);
   }
+
+  SigninManager* signin =
+      SigninManagerFactory::GetInstance()->GetForProfile(
+          profile()->GetOriginalProfile());
+  if (signin)
+    signin->AddSigninPrefObserver(this);

[Andrew T Wilson (Slow), 2013/02/04 15:41:48]

I don't think we want to define a new SigninPrefObserver. I think it's probably
better to just have BrowserCommandController listen to changes to the pref
directly. That's what we do elsewhere in this file for things like
kIncognitoModeAvailability.

[Adrian Kuegel, 2013/02/05 10:55:15]

I removed the SigninPrefObserver now. You are right, we don't need it, I just
used the ProfileSyncServiceObserver as an example and I thought I should do it
similarly.
Anyway, I think here I cannot use the profile_pref_registrar, because it would
not work in incognito mode. I need an observer of the preferences of the
original profile.

 }
 
 BrowserCommandController::~BrowserCommandController() {
+  SigninManager* signin = SigninManagerFactory::GetInstance()->GetForProfile(
+      profile()->GetOriginalProfile());
+  if (signin)
+    signin->RemoveSigninPrefObserver(this);
+
   // TabRestoreService may have been shutdown by the time we get here. Don't
   // trigger creating it.
   TabRestoreService* tab_restore_service =
@@ -742,6 +755,17 @@ void BrowserCommandController::OnProfileAvatarChanged(
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// BrowserCommandController, SigninPrefObserver implementation:
+
+void BrowserCommandController::OnSigninAllowedPrefChange(bool signin_allowed) {
+  // For unit tests, we don't have a window.
+  if (!window())
+    return;
+  const bool show_main_ui = IsShowingMainUI(window()->IsFullscreen());
+  command_updater_.UpdateCommandEnabled(IDC_SHOW_SYNC_SETUP,
+      show_main_ui && signin_allowed);
+}
+
 // BrowserCommandController, TabStripModelObserver implementation:
 
 void BrowserCommandController::TabInsertedAt(WebContents* contents,
@@ -881,7 +905,9 @@ void BrowserCommandController::InitCommandState() {
                                         !profile()->IsGuestSession() &&
                                         !profile()->IsOffTheRecord());
 
-  command_updater_.UpdateCommandEnabled(IDC_SHOW_SIGNIN, true);
+  command_updater_.UpdateCommandEnabled(
+      IDC_SHOW_SYNC_SETUP,
+      profile()->GetOriginalProfile()->IsSigninAllowed());
 
   // Initialize other commands based on the window type.
   bool normal_window = browser_->is_type_tabbed();
@@ -1116,6 +1142,8 @@ void BrowserCommandController::UpdateCommandsForFullscreenMode(
   // Show various bits of UI
   command_updater_.UpdateCommandEnabled(IDC_DEVELOPER_MENU, show_main_ui);
   command_updater_.UpdateCommandEnabled(IDC_FEEDBACK, show_main_ui);
+  command_updater_.UpdateCommandEnabled(IDC_SHOW_SYNC_SETUP,
+      show_main_ui && profile()->GetOriginalProfile()->IsSigninAllowed());
 
   // Settings page/subpages are forced to open in normal mode. We disable these
   // commands when incognito is forced.