Fix flakiness of DesktopDragDropClientAuraX11Tests

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.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_window_tree_host_x11.h"
 
 #include <X11/extensions/shape.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xregion.h>
@@ skipping 273 matching lines @@
 scoped_ptr<corewm::Tooltip> DesktopWindowTreeHostX11::CreateTooltip() {
   return scoped_ptr<corewm::Tooltip>(
       new corewm::TooltipAura(gfx::SCREEN_TYPE_NATIVE));
 }
 
 scoped_ptr<aura::client::DragDropClient>
 DesktopWindowTreeHostX11::CreateDragDropClient(
     DesktopNativeCursorManager* cursor_manager) {
   drag_drop_client_ = new DesktopDragDropClientAuraX11(
       window(), cursor_manager, xdisplay_, xwindow_);
+  drag_drop_client_->Init();
   return scoped_ptr<aura::client::DragDropClient>(drag_drop_client_).Pass();
 }
 
 void DesktopWindowTreeHostX11::Close() {
   // TODO(erg): Might need to do additional hiding tasks here.
   delayed_resize_task_.Cancel();
 
   if (!close_widget_factory_.HasWeakPtrs()) {
     // And we delay the close so that if we are called from an ATL callback,
     // we don't destroy the window before the callback returned (as the caller
@@ skipping 1592 matching lines @@
   if (linux_ui) {
     ui::NativeTheme* native_theme = linux_ui->GetNativeTheme(window);
     if (native_theme)
       return native_theme;
   }
 
   return ui::NativeTheme::instance();
 }
 
 }  // namespace views