Add display task to trigger display configuration

ui/display/chromeos/x11/native_display_delegate_x11.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 "ui/display/chromeos/x11/native_display_delegate_x11.h"
 
 #include <X11/Xatom.h>
 #include <X11/Xlib.h>
 #include <X11/extensions/dpms.h>
 #include <X11/extensions/Xrandr.h>
@@ skipping 174 matching lines @@
       DisplaySnapshotX11* output =
           InitDisplaySnapshot(output_id, output_info, &last_used_crtcs, i);
       cached_outputs_.push_back(output);
     }
     XRRFreeOutputInfo(output_info);
   }
 
   return cached_outputs_.get();
 }
 
+void NativeDisplayDelegateX11::GetDisplays(
+    const GetDisplaysCallback& callback) {
+  callback.Run(GetDisplays());
+}
+
 void NativeDisplayDelegateX11::AddMode(const DisplaySnapshot& output,
                                        const DisplayMode* mode) {
   CHECK(screen_) << "Server not grabbed";
   CHECK(mode) << "Must add valid mode";
 
   const DisplaySnapshotX11& x11_output =
       static_cast<const DisplaySnapshotX11&>(output);
   RRMode mode_id = static_cast<const DisplayModeX11*>(mode)->mode_id();
 
   VLOG(1) << "AddDisplayMode: output=" << x11_output.output()
@@ skipping 442 matching lines @@
   XSetForeground(display_, gc, color.pixel);
   XSetFillStyle(display_, gc, FillSolid);
   int width = DisplayWidth(display_, DefaultScreen(display_));
   int height = DisplayHeight(display_, DefaultScreen(display_));
   XFillRectangle(display_, window_, gc, 0, 0, width, height);
   XFreeGC(display_, gc);
   XFreeColors(display_, colormap, &color.pixel, 1, 0);
 }
 
 }  // namespace ui