mus: Implement interwindow drag and drop

services/ui/ws/server_window.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 "services/ui/ws/server_window.h"
 
 #include <inttypes.h>
 #include <stddef.h>
 
 #include "base/strings/stringprintf.h"
@@ skipping 169 matching lines @@
 }
 
 void ServerWindow::SetHitTestMask(const gfx::Rect& mask) {
   hit_test_mask_.reset(new gfx::Rect(mask));
 }
 
 void ServerWindow::ClearHitTestMask() {
   hit_test_mask_.reset();
 }
 
+void ServerWindow::SetCanAcceptDrops(bool accepts_drops) {
+  accepts_drops_ = accepts_drops;
+}
+
 const ServerWindow* ServerWindow::GetRoot() const {
   return delegate_->GetRootWindow(this);
 }
 
 ServerWindow* ServerWindow::GetChildWindow(const WindowId& window_id) {
   if (id_ == window_id)
     return this;
 
   for (ServerWindow* child : children_) {
     ServerWindow* window = child->GetChildWindow(window_id);
@@ skipping 253 matching lines @@
 }
 
 // static
 ServerWindow** ServerWindow::GetStackingTarget(ServerWindow* window) {
   return &window->stacking_target_;
 }
 
 }  // namespace ws
 
 }  // namespace ui