ash: Start/stop observing KeyboardController via ShellObserver

ash/root_window_controller.cc

 // 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 "ash/root_window_controller.h"
 
 #include <algorithm>
 #include <queue>
 #include <vector>
 
@@ skipping 655 matching lines @@
       wm::GetWindowForFullscreenMode(WmWindow::Get(GetRootWindow())));
 }
 
 void RootWindowController::ActivateKeyboard(
     keyboard::KeyboardController* keyboard_controller) {
   if (!keyboard::IsKeyboardEnabled() ||
       GetContainer(kShellWindowId_VirtualKeyboardContainer)) {
     return;
   }
   DCHECK(keyboard_controller);
-  keyboard_controller->AddObserver(wm_shelf_->shelf_layout_manager());
-  keyboard_controller->AddObserver(panel_layout_manager());
-  keyboard_controller->AddObserver(docked_window_layout_manager());
-  keyboard_controller->AddObserver(workspace_controller()->layout_manager());
-  keyboard_controller->AddObserver(
-      always_on_top_controller_->GetLayoutManager());
-  Shell::GetInstance()->NotifyVirtualKeyboardActivated(true);
   aura::Window* parent = GetContainer(kShellWindowId_ImeWindowParentContainer);
   DCHECK(parent);
   aura::Window* keyboard_container = keyboard_controller->GetContainerWindow();
   keyboard_container->set_id(kShellWindowId_VirtualKeyboardContainer);
   parent->AddChild(keyboard_container);
+  // Notify observers after adding keyboard container because various layout
+  // managers are using the root window of the container window to decide
+  // whether the keyboard is relevant to them.
+  Shell::GetInstance()->NotifyVirtualKeyboardActivated(true);
 }
 
 void RootWindowController::DeactivateKeyboard(
     keyboard::KeyboardController* keyboard_controller) {
   if (!keyboard_controller ||
       !keyboard_controller->keyboard_container_initialized()) {
     return;
   }
   aura::Window* keyboard_container = keyboard_controller->GetContainerWindow();
   if (keyboard_container->GetRootWindow() == GetRootWindow()) {
     aura::Window* parent =
         GetContainer(kShellWindowId_ImeWindowParentContainer);
     DCHECK(parent);
     // Virtual keyboard may be deactivated while still showing, hide the
     // keyboard before removing it from view hierarchy.
     keyboard_controller->HideKeyboard(
         keyboard::KeyboardController::HIDE_REASON_AUTOMATIC);
+    // Notify observers before removing keyboard container because various
+    // layout managers are using the root window of the container window to
+    // decide whether the keyboard is relevant to them.
+    Shell::GetInstance()->NotifyVirtualKeyboardActivated(false);
     parent->RemoveChild(keyboard_container);
-    keyboard_controller->RemoveObserver(wm_shelf_->shelf_layout_manager());
-    keyboard_controller->RemoveObserver(panel_layout_manager());
-    keyboard_controller->RemoveObserver(docked_window_layout_manager());
-    keyboard_controller->RemoveObserver(
-        workspace_controller()->layout_manager());
-    keyboard_controller->RemoveObserver(
-        always_on_top_controller_->GetLayoutManager());
-    Shell::GetInstance()->NotifyVirtualKeyboardActivated(false);
   }
 }
 
 bool RootWindowController::IsVirtualKeyboardWindow(aura::Window* window) {
   aura::Window* parent = GetContainer(kShellWindowId_ImeWindowParentContainer);
   return parent ? parent->Contains(window) : false;
 }
 
 void RootWindowController::SetTouchAccessibilityAnchorPoint(
     const gfx::Point& anchor_point) {
@@ skipping 429 matching lines @@
     EnableTouchHudProjection();
   else
     DisableTouchHudProjection();
 }
 
 RootWindowController* GetRootWindowController(const aura::Window* root_window) {
   return root_window ? GetRootWindowSettings(root_window)->controller : nullptr;
 }
 
 }  // namespace ash