chromeos: Fix shelf appearing at login screen under mash

ash/aura/wm_shell_aura.cc

 // Copyright 2016 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 "ash/aura/wm_shell_aura.h"
 
 #include <utility>
 
 #include "ash/aura/key_event_watcher_aura.h"
 #include "ash/aura/pointer_watcher_adapter.h"
@@ skipping 228 matching lines @@
 void WmShellAura::OnOverviewModeStarting() {
   for (auto& observer : *shell_observers())
     observer.OnOverviewModeStarting();
 }
 
 void WmShellAura::OnOverviewModeEnded() {
   for (auto& observer : *shell_observers())
     observer.OnOverviewModeEnded();
 }
 
+void WmShellAura::OnUserSessionStateActive() {
+  CreateShelf();

[msw, 2016/12/16 16:26:20]

It's a bit odd that we'll potentially call CreateShelf multiple times.

[James Cook, 2016/12/20 04:02:42]

OK, fixed that.

(I could also just rename this function to CreateShelfIfNeeded().)

+  Shell::GetInstance()->CreateKeyboard();

[msw, 2016/12/16 16:26:20]

Is this necessary here? Shouldn't it be triggered when the keyboard is needed?

[James Cook, 2016/12/20 04:02:42]

The virtual keyboard can be shown at the login screen before the shelf is shown,
but seems to destroy itself during login and needs to be recreated. It adds a
bunch of shelf-observers, so needs to be done after shelf creation. It also gets
torn down and recreated after multiprofile switch. It might be due to accessing
the active user's profile in the webui code.

Regardless, this is what the old code did and I'm afraid of breaking it.

+}
+
 SessionStateDelegate* WmShellAura::GetSessionStateDelegate() {
   return Shell::GetInstance()->session_state_delegate();
 }
 
 void WmShellAura::AddActivationObserver(WmActivationObserver* observer) {
   if (!added_activation_observer_) {
     added_activation_observer_ = true;
     Shell::GetInstance()->activation_client()->AddObserver(this);
   }
   activation_observers_.AddObserver(observer);
@@ skipping 68 matching lines @@
   for (auto& observer : display_observers_)
     observer.OnDisplayConfigurationChanging();
 }
 
 void WmShellAura::OnDisplayConfigurationChanged() {
   for (auto& observer : display_observers_)
     observer.OnDisplayConfigurationChanged();
 }
 
 }  // namespace ash