Introdcue AshWindowTreeHost and move ash/chrome specific code in WTH to ash.

ash/root_window_controller.cc

Index: ash/root_window_controller.cc
diff --git a/ash/root_window_controller.cc b/ash/root_window_controller.cc
index 3b1fbce32464198103344831a8c90055172747f7..5157cd356c544b3d5c4cbc4d50395c10c6de1f12 100644
--- a/ash/root_window_controller.cc
+++ b/ash/root_window_controller.cc
@@ -15,6 +15,7 @@
 #include "ash/display/display_manager.h"
 #include "ash/focus_cycler.h"
 #include "ash/high_contrast/high_contrast_controller.h"
+#include "ash/host/ash_window_tree_host.h"
 #include "ash/root_window_settings.h"
 #include "ash/session_state_delegate.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ -264,20 +265,20 @@ class EmptyWindowDelegate : public aura::WindowDelegate {
 
 namespace internal {
 
-void RootWindowController::CreateForPrimaryDisplay(aura::WindowTreeHost* host) {
+void RootWindowController::CreateForPrimaryDisplay(AshWindowTreeHost* host) {
   RootWindowController* controller = new RootWindowController(host);
   controller->Init(RootWindowController::PRIMARY,
                    Shell::GetInstance()->delegate()->IsFirstRunAfterBoot());
 }
 
 void RootWindowController::CreateForSecondaryDisplay(
-    aura::WindowTreeHost* host) {
+    AshWindowTreeHost* host) {
   RootWindowController* controller = new RootWindowController(host);
   controller->Init(RootWindowController::SECONDARY, false /* first run */);
 }
 
 void RootWindowController::CreateForVirtualKeyboardDisplay(
-    aura::WindowTreeHost* host) {
+    AshWindowTreeHost* host) {
   RootWindowController* controller = new RootWindowController(host);
   controller->Init(RootWindowController::VIRTUAL_KEYBOARD,
                    false /* first run */);
@@ -310,7 +311,7 @@ aura::Window* RootWindowController::GetContainerForWindow(
 
 RootWindowController::~RootWindowController() {
   Shutdown();
-  host_.reset();
+  ash_host_.reset();
   // The CaptureClient needs to be around for as long as the RootWindow is
   // valid.
   capture_client_.reset();
@@ -386,7 +387,7 @@ aura::Window* RootWindowController::GetContainer(int container_id) {
 }
 
 const aura::Window* RootWindowController::GetContainer(int container_id) const {
-  return host_->window()->GetChildById(container_id);
+  return ash_host_->AsWindowTreeHost()->window()->GetChildById(container_id);
 }
 
 void RootWindowController::ShowShelf() {
@@ -655,8 +656,8 @@ void RootWindowController::DeactivateKeyboard(
 ////////////////////////////////////////////////////////////////////////////////
 // RootWindowController, private:
 
-RootWindowController::RootWindowController(aura::WindowTreeHost* host)
-    : host_(host),
+RootWindowController::RootWindowController(AshWindowTreeHost* ash_host)
+    : ash_host_(ash_host),
       root_window_layout_(NULL),
       docked_layout_manager_(NULL),
       panel_layout_manager_(NULL),
@@ -675,7 +676,7 @@ void RootWindowController::Init(RootWindowType root_window_type,
   Shell* shell = Shell::GetInstance();
   shell->InitRootWindow(root_window());
 
-  host_->SetCursor(ui::kCursorPointer);
+  ash_host_->AsWindowTreeHost()->SetCursor(ui::kCursorPointer);
   CreateContainersInRootWindow(root_window());
 
   if (root_window_type == VIRTUAL_KEYBOARD) {
@@ -703,7 +704,7 @@ void RootWindowController::Init(RootWindowType root_window_type,
     root_window_layout()->OnWindowResized();
     shell->desktop_background_controller()->OnRootWindowAdded(root_window());
     shell->high_contrast_controller()->OnRootWindowAdded(root_window());
-    host_->Show();
+    ash_host_->AsWindowTreeHost()->Show();
 
     // Create a shelf if a user is already logged in.
     if (shell->session_state_delegate()->NumberOfLoggedInUsers())