Cancel drag if display configuration changes.

ui/views/widget/x11_desktop_window_move_client.cc

Index: ui/views/widget/x11_desktop_window_move_client.cc
diff --git a/ui/views/widget/x11_desktop_window_move_client.cc b/ui/views/widget/x11_desktop_window_move_client.cc
index 329a65688a45bfea4880e02c2ccb705438129f6a..adb6ff3b609a202480f39306280c0005f1ab8e81 100644
--- a/ui/views/widget/x11_desktop_window_move_client.cc
+++ b/ui/views/widget/x11_desktop_window_move_client.cc
@@ -69,8 +69,9 @@ ui::EventResult X11DesktopWindowMoveClient::PreHandleGestureEvent(
   return ui::ER_UNHANDLED;
 }
 
-void X11DesktopWindowMoveClient::RunMoveLoop(aura::Window* source,
-                                             const gfx::Point& drag_offset) {
+aura::client::WindowMoveResult X11DesktopWindowMoveClient::RunMoveLoop(
+    aura::Window* source,
+    const gfx::Point& drag_offset) {
   DCHECK(!in_move_loop_);  // Can only handle one nested loop at a time.
   in_move_loop_ = true;
   window_offset_ = drag_offset;
@@ -94,7 +95,7 @@ void X11DesktopWindowMoveClient::RunMoveLoop(aura::Window* source,
   XUngrabServer(display);
   if (ret != GrabSuccess) {
     DLOG(ERROR) << "Grabbing new tab for dragging failed: " << ret;
-    return;
+    return aura::client::MOVE_CANCELED;
   }
 
   MessageLoopForUI* loop = MessageLoopForUI::current();
@@ -102,6 +103,7 @@ void X11DesktopWindowMoveClient::RunMoveLoop(aura::Window* source,
   base::RunLoop run_loop(aura::Env::GetInstance()->GetDispatcher());
   quit_closure_ = run_loop.QuitClosure();
   run_loop.Run();
+  return aura::client::MOVE_SUCCESSFUL;
 }
 
 void X11DesktopWindowMoveClient::EndMoveLoop() {