Remove an ash::Shell access from ChromeLauncherController

ChromeLauncherController is resetting the virtual keyboard when the
active user changes. However, the SessionController (which is already
in ash) can have an observer that can listen to the same event. By
making the VirtualKeyboardController a SessionObserver, we can move
the keyboard reset to the other process to make it mustash-friendly.

Bug: 826391
Change-Id: I70b622105c3bf6dd415b1eee5f0521a38b6d1bf1
Reviewed-on: https://chromium-review.googlesource.com/1100672
Commit-Queue: Blake O'Hare <blakeo@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569926}

ash/keyboard/virtual_keyboard_controller.cc

@@ -11,6 +11,7 @@
 #include "ash/keyboard/keyboard_ui.h"
 #include "ash/public/cpp/config.h"
 #include "ash/root_window_controller.h"
+#include "ash/session/session_controller.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
@@ -84,6 +85,7 @@ VirtualKeyboardController::VirtualKeyboardController()
       has_touchscreen_(false),
       ignore_external_keyboard_(false) {
   Shell::Get()->tablet_mode_controller()->AddObserver(this);
+  Shell::Get()->session_controller()->AddObserver(this);
   ui::InputDeviceManager::GetInstance()->AddObserver(this);
   UpdateDevices();
 
@@ -97,6 +99,8 @@ VirtualKeyboardController::VirtualKeyboardController()
 VirtualKeyboardController::~VirtualKeyboardController() {
   if (Shell::Get()->tablet_mode_controller())
     Shell::Get()->tablet_mode_controller()->RemoveObserver(this);
+  if (Shell::Get()->session_controller())
+    Shell::Get()->session_controller()->RemoveObserver(this);
   ui::InputDeviceManager::GetInstance()->RemoveObserver(this);
 
   // Reset the emoji panel callback
@@ -309,4 +313,11 @@ void VirtualKeyboardController::OnKeyboardHidden() {
   }
 }
 
+void VirtualKeyboardController::OnActiveUserSessionChanged(
+    const AccountId& account_id) {
+  // Force on-screen keyboard to reset.
+  if (keyboard::IsKeyboardEnabled())
+    Shell::Get()->EnableKeyboard();
+}
+
 }  // namespace ash

ash/keyboard/virtual_keyboard_controller.h

@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include "ash/ash_export.h"
+#include "ash/session/session_observer.h"
 #include "ash/wm/tablet_mode/tablet_mode_observer.h"
 #include "base/macros.h"
 #include "ui/base/ime/chromeos/public/interfaces/ime_keyset.mojom.h"
@@ -25,7 +26,8 @@ class ASH_EXPORT VirtualKeyboardController
     : public TabletModeObserver,
       public ui::InputDeviceEventObserver,
       public keyboard::KeyboardLayoutDelegate,
-      public keyboard::KeyboardControllerObserver {
+      public keyboard::KeyboardControllerObserver,
+      public SessionObserver {
  public:
   VirtualKeyboardController();
   ~VirtualKeyboardController() override;
@@ -56,6 +58,9 @@ class ASH_EXPORT VirtualKeyboardController
   void OnKeyboardClosed() override;
   void OnKeyboardHidden() override;
 
+  // SessionObserver
+  void OnActiveUserSessionChanged(const AccountId& account_id) override;
+
  private:
   // Updates the list of active input devices.
   void UpdateDevices();

chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc

@@ -552,12 +552,6 @@ void ChromeLauncherController::ActiveUserChanged(
   // Restore the order of running, but unpinned applications for the activated
   // user.
   RestoreUnpinnedRunningApplicationOrder(user_email);
-  // TODO(crbug.com/557406): Fix this interaction pattern in Mash.
-  if (features::IsAshInBrowserProcess()) {
-    // Force on-screen keyboard to reset.
-    if (keyboard::IsKeyboardEnabled())
-      ash::Shell::Get()->EnableKeyboard();
-  }
 }
 
 void ChromeLauncherController::AdditionalUserAddedToSession(Profile* profile) {