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

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
index 028b6f59ca453fee877e2e9f4af38c967996cf38..ed7ca42edd85e269f563e2397047b83dbbba5fcc 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
@@ -762,10 +762,6 @@ void DesktopWindowTreeHostX11::Hide() {
   native_widget_delegate_->OnNativeWidgetVisibilityChanged(false);
 }
 
-void DesktopWindowTreeHostX11::ToggleFullScreen() {
-  NOTIMPLEMENTED();
-}
-
 gfx::Rect DesktopWindowTreeHostX11::GetBounds() const {
   return bounds_;
 }
@@ -809,13 +805,6 @@ void DesktopWindowTreeHostX11::SetBounds(const gfx::Rect& bounds) {
     compositor()->ScheduleRedrawRect(gfx::Rect(bounds.size()));
 }
 
-gfx::Insets DesktopWindowTreeHostX11::GetInsets() const {
-  return gfx::Insets();
-}
-
-void DesktopWindowTreeHostX11::SetInsets(const gfx::Insets& insets) {
-}
-
 gfx::Point DesktopWindowTreeHostX11::GetLocationOnNativeScreen() const {
   return bounds_.origin();
 }
@@ -867,15 +856,6 @@ bool DesktopWindowTreeHostX11::QueryMouseLocation(
           win_y_return >= 0 && win_y_return < bounds_.height());
 }
 
-bool DesktopWindowTreeHostX11::ConfineCursorToRootWindow() {
-  NOTIMPLEMENTED();
-  return false;
-}
-
-void DesktopWindowTreeHostX11::UnConfineCursor() {
-  NOTIMPLEMENTED();
-}
-
 void DesktopWindowTreeHostX11::SetCursorNative(gfx::NativeCursor cursor) {
   XDefineCursor(xdisplay_, xwindow_, cursor.platform());
 }