Ensure DesktopDragDropClientAuraX11::StartEndMoveLoopTimer() is called before the move loop is ended

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc

 // Copyright (c) 2012 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/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h"
 
 #include <X11/Xatom.h>
 
 #include "base/event_types.h"
 #include "base/lazy_instance.h"
@@ skipping 669 matching lines @@
         // the XdndStatus and XdndFinished messages.
         StartEndMoveLoopTimer();
         return;
       }
 
       move_loop_.EndMoveLoop();
       return;
     }
 
     if (negotiated_operation_ != ui::DragDropTypes::DRAG_NONE) {
+      // Start timer to end the move loop if the target takes too long to send
+      // an XdndFinished message. It is important that StartEndMoveLoopTimer()
+      // is called before SendXdndDrop() because SendXdndDrop()
+      // sends XdndFinished synchronously if the drop target is a Chrome
+      // window.
+      StartEndMoveLoopTimer();
+
       // We have negotiated an action with the other end.
       source_state_ = SOURCE_STATE_DROPPED;
       SendXdndDrop(source_current_window_);
-
-      // Start timer to end the move loop if the target takes too long to send
-      // an XdndFinished message.
-      StartEndMoveLoopTimer();
       return;
     }
   }
 
   move_loop_.EndMoveLoop();
 }
 
 void DesktopDragDropClientAuraX11::OnMoveLoopEnded() {
   if (source_current_window_ != None) {
     SendXdndLeave(source_current_window_);
@@ skipping 315 matching lines @@
   xev.xclient.window = dest_window;
   xev.xclient.data.l[0] = xwindow_;
   xev.xclient.data.l[1] = 0;
   xev.xclient.data.l[2] = CurrentTime;
   xev.xclient.data.l[3] = None;
   xev.xclient.data.l[4] = None;
   SendXClientEvent(dest_window, &xev);
 }
 
 }  // namespace views