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

ash/host/ash_remote_window_tree_host_win.cc

+// Copyright 2014 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/host/ash_remote_window_tree_host_win.h"
+
+#include "ash/host/root_window_transformer.h"
+#include "ui/gfx/geometry/insets.h"
+#include "ui/gfx/transform.h"
+
+namespace ash {
+namespace {
+AshRemoteWindowTreeHostWin* g_instance = NULL;
+}
+
+// static
+void AshRemoteWindowTreeHostWin::Init() {
+  DCHECK(!g_instance);
+  g_instance = new AshRemoteWindowTreeHostWin();
+  aura::RemoteWindowTreeHostWin::SetInstance(g_instance);
+  CHECK_EQ(g_instance, aura::RemoteWindowTreeHostWin::Instance());
+}
+
+// static
+AshRemoteWindowTreeHostWin* AshRemoteWindowTreeHostWin::GetInstance() {
+  if (!g_instance)
+    Init();
+  CHECK_EQ(g_instance, aura::RemoteWindowTreeHostWin::Instance());
+  return g_instance;
+}
+
+AshRemoteWindowTreeHostWin::AshRemoteWindowTreeHostWin()
+    : aura::RemoteWindowTreeHostWin(gfx::Rect()), transformer_helper_(this) {
+  g_instance = this;
+}
+
+AshRemoteWindowTreeHostWin::~AshRemoteWindowTreeHostWin() { g_instance = NULL; }
+
+void AshRemoteWindowTreeHostWin::ToggleFullScreen() {}
+
+bool AshRemoteWindowTreeHostWin::ConfineCursorToRootWindow() { return false; }
+
+void AshRemoteWindowTreeHostWin::UnConfineCursor() {}
+
+void AshRemoteWindowTreeHostWin::SetRootWindowTransformer(
+    scoped_ptr<RootWindowTransformer> transformer) {
+  transformer_helper_.SetRootWindowTransformer(transformer.Pass());
+}
+
+aura::WindowTreeHost* AshRemoteWindowTreeHostWin::AsWindowTreeHost() {
+  return this;
+}
+
+gfx::Transform AshRemoteWindowTreeHostWin::GetRootTransform() const {
+  return transformer_helper_.GetTransform();
+}
+
+void AshRemoteWindowTreeHostWin::SetRootTransform(
+    const gfx::Transform& transform) {
+  transformer_helper_.SetTransform(transform);
+}
+
+gfx::Transform AshRemoteWindowTreeHostWin::GetInverseRootTransform() const {
+  return transformer_helper_.GetInverseTransform();
+}
+
+void AshRemoteWindowTreeHostWin::UpdateRootWindowSize(
+    const gfx::Size& host_size) {
+  transformer_helper_.UpdateWindowSize(host_size);
+}
+
+}  // namespace ash