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

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
index 2fc499bbef576c54f3bedeef29bc3b64141c21e6..ebbd14bb9094a20463e32200e1c544ecee2e4bf6 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
@@ -449,10 +449,6 @@ void DesktopWindowTreeHostWin::Hide() {
     message_handler_->Hide();
 }
 
-void DesktopWindowTreeHostWin::ToggleFullScreen() {
-  SetWindowTransparency();
-}
-
 // GetBounds and SetBounds work in pixel coordinates, whereas other get/set
 // methods work in DIP.
 
@@ -500,13 +496,6 @@ void DesktopWindowTreeHostWin::SetBounds(const gfx::Rect& bounds) {
     HandleClientSizeChanged(new_expanded.size());
 }
 
-gfx::Insets DesktopWindowTreeHostWin::GetInsets() const {
-  return gfx::Insets();
-}
-
-void DesktopWindowTreeHostWin::SetInsets(const gfx::Insets& insets) {
-}
-
 gfx::Point DesktopWindowTreeHostWin::GetLocationOnNativeScreen() const {
   return GetBounds().origin();
 }
@@ -533,16 +522,6 @@ bool DesktopWindowTreeHostWin::QueryMouseLocation(gfx::Point* location_return) {
   return true;
 }
 
-bool DesktopWindowTreeHostWin::ConfineCursorToRootWindow() {
-  RECT window_rect = window()->GetBoundsInScreen().ToRECT();
-  ::ClipCursor(&window_rect);
-  return true;
-}
-
-void DesktopWindowTreeHostWin::UnConfineCursor() {
-  ::ClipCursor(NULL);
-}
-
 void DesktopWindowTreeHostWin::PostNativeEvent(
     const base::NativeEvent& native_event) {
 }