Adds WmWindow and converts WindowState to use it

ash/wm/dock/docked_window_layout_manager.cc

Index: ash/wm/dock/docked_window_layout_manager.cc
diff --git a/ash/wm/dock/docked_window_layout_manager.cc b/ash/wm/dock/docked_window_layout_manager.cc
index 87144109f02156d9698577bb155dd16477caf21e..621292f3b0dd25d4d4fd27e3e236df2074975bce 100644
--- a/ash/wm/dock/docked_window_layout_manager.cc
+++ b/ash/wm/dock/docked_window_layout_manager.cc
@@ -17,6 +17,7 @@
 #include "ash/wm/window_properties.h"
 #include "ash/wm/window_resizer.h"
 #include "ash/wm/window_state.h"
+#include "ash/wm/window_state_aura.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace_controller.h"
 #include "base/auto_reset.h"
@@ -834,7 +835,7 @@ void DockedWindowLayoutManager::OnBackgroundUpdated(
 void DockedWindowLayoutManager::OnPreWindowStateTypeChange(
     wm::WindowState* window_state,
     wm::WindowStateType old_type) {
-  aura::Window* window = window_state->window();
+  aura::Window* window = window_state->aura_window();
   if (IsPopupOrTransient(window))
     return;
   // The window property will still be set, but no actual change will occur
@@ -959,7 +960,7 @@ void DockedWindowLayoutManager::MaybeMinimizeChildrenExcept(
 
 void DockedWindowLayoutManager::MinimizeDockedWindow(
     wm::WindowState* window_state) {
-  DCHECK(!IsPopupOrTransient(window_state->window()));
+  DCHECK(!IsPopupOrTransient(window_state->aura_window()));
   window_state->window()->Hide();
   if (window_state->IsActive())
     window_state->Deactivate();
@@ -968,7 +969,7 @@ void DockedWindowLayoutManager::MinimizeDockedWindow(
 
 void DockedWindowLayoutManager::RestoreDockedWindow(
     wm::WindowState* window_state) {
-  aura::Window* window = window_state->window();
+  aura::Window* window = window_state->aura_window();
   DCHECK(!IsPopupOrTransient(window));
   // Always place restored window at the bottom shuffling the other windows up.
   // TODO(varkha): add a separate container for docked windows to keep track