mash: Run pre-unlock animation via SessionController

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 1d7e60c4a670b5cf3c448d3b68712a16eb687cd9..96c52acff7c1d6a9357025dc3263025aeb0995b1 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -333,20 +333,6 @@ void Shell::OnAppTerminating() {
     observer.OnAppTerminating();
 }
 
-void Shell::OnLockStateChanged(bool locked) {
-  for (auto& observer : shell_observers_)
-    observer.OnLockStateChanged(locked);
-#ifndef NDEBUG
-  // Make sure that there is no system modal in Lock layer when unlocked.
-  if (!locked) {
-    aura::Window::Windows containers = wm::GetContainersFromAllRootWindows(
-        kShellWindowId_LockSystemModalContainer, GetPrimaryRootWindow());
-    for (aura::Window* container : containers)
-      DCHECK(container->children().empty());
-  }
-#endif
-}
-
 void Shell::OnCastingSessionStartedOrStopped(bool started) {
   for (auto& observer : shell_observers_)
     observer.OnCastingSessionStartedOrStopped(started);
@@ -1251,6 +1237,20 @@ void Shell::LoginStatusChanged(LoginStatus login_status) {
     observer.OnLoginStateChanged(login_status);
 }
 
+void Shell::OnLockStateChanged(bool locked) {
+  for (auto& observer : shell_observers_)
+    observer.OnLockStateChanged(locked);

[James Cook, 2017/04/07 20:26:55]

Aside: It's unfortunate that we have Shell observers for LockStateChanged and
also SessionStateObservers. Maybe not for this CL, but WDYT of converting
ShellObservers for OnLockStateChanged() to SessionStateObservers?

[xiyuan, 2017/04/07 21:50:01]

SGTM. Added a TODO. I have thought about doing that. A follow up CL would be
better than in this CL. 

+#ifndef NDEBUG
+  // Make sure that there is no system modal in Lock layer when unlocked.
+  if (!locked) {
+    aura::Window::Windows containers = wm::GetContainersFromAllRootWindows(
+        kShellWindowId_LockSystemModalContainer, GetPrimaryRootWindow());
+    for (aura::Window* container : containers)
+      DCHECK(container->children().empty());
+  }
+#endif
+}
+
 void Shell::OnPrefServiceInitialized(
     std::unique_ptr<::PrefService> pref_service) {
   if (!instance_)