mash: Use the new mus drag and drop API to get drag working in mash.

ui/views/mus/drag_drop_client_mus.cc

+// Copyright 2016 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/mus/drag_drop_client_mus.h"
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "services/ui/public/cpp/window.h"
+#include "ui/aura/window.h"
+#include "ui/views/mus/os_exchange_data_provider_mus.h"
+
+namespace views {
+namespace {
+
+DragDropClientMus* current_dragging_client = nullptr;
+
+}  // namespace
+
+DragDropClientMus::DragDropClientMus(ui::Window* ui_window)
+    : ui_window_(ui_window) {}
+
+DragDropClientMus::~DragDropClientMus() {}
+
+int DragDropClientMus::StartDragAndDrop(
+    const ui::OSExchangeData& data,
+    aura::Window* root_window,
+    aura::Window* source_window,
+    const gfx::Point& screen_location,
+    int drag_operations,
+    ui::DragDropTypes::DragEventSource source) {
+  std::map<std::string, std::vector<uint8_t>> drag_data =
+      static_cast<const OSExchangeDataProviderMus&>(data.provider()).GetData();
+
+  // TODO(erg): Right now, I'm passing the cursor_location, but maybe I want to
+  // pass OSExchangeData::GetDragImageOffset() instead?
+
+  bool success = false;
+  gfx::Point cursor_location = screen_location;
+  uint32_t action_taken = ui::mojom::kDropEffectNone;
+  current_dragging_client = this;
+  ui_window_->PerformDragDrop(
+      drag_data, drag_operations, cursor_location,
+      *data.provider().GetDragImage().bitmap(),
+      base::Bind(&DragDropClientMus::OnMoveLoopEnd, base::Unretained(this),
+                 &success, &action_taken));
+
+  base::MessageLoop* loop = base::MessageLoop::current();
+  base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
+  base::RunLoop run_loop;
+
+  runloop_quit_closure_ = run_loop.QuitClosure();
+  run_loop.Run();
+  current_dragging_client = nullptr;
+
+  return action_taken;
+}
+
+void DragDropClientMus::DragUpdate(aura::Window* target,
+                                   const ui::LocatedEvent& event) {
+  // Only called on OSX.
+  NOTREACHED();
+}
+
+void DragDropClientMus::Drop(aura::Window* target,
+                             const ui::LocatedEvent& event) {
+  // Only called on OSX.
+  NOTREACHED();
+}
+
+void DragDropClientMus::DragCancel() {
+  ui_window_->CancelDragDrop();
+}
+
+bool DragDropClientMus::IsDragDropInProgress() {
+  return !!current_dragging_client;
+}
+
+void DragDropClientMus::OnMoveLoopEnd(bool* out_success,
+                                      uint32_t* out_action,
+                                      bool in_success,
+                                      uint32_t in_action) {
+  *out_success = in_success;
+  *out_action = in_action;
+  runloop_quit_closure_.Run();
+}
+
+}  // namespace views