mozart: Initial commit of the view manager.

services/ui/view_manager/view_layout_request.h

+// Copyright 2015 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.
+
+#ifndef SERVICES_UI_VIEW_MANAGER_VIEW_LAYOUT_REQUEST_H_
+#define SERVICES_UI_VIEW_MANAGER_VIEW_LAYOUT_REQUEST_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "mojo/services/ui/views/interfaces/layouts.mojom.h"
+
+namespace view_manager {
+
+using ViewLayoutCallback = base::Callback<void(mojo::ui::ViewLayoutInfoPtr)>;
+
+// Describes a pending layout request for a view.
+class ViewLayoutRequest {
+ public:
+  explicit ViewLayoutRequest(mojo::ui::ViewLayoutParamsPtr layout_params);
+
+  // Dispatches null layout info automatically if DispatchLayoutInfo was not
+  // called.
+  ~ViewLayoutRequest();
+
+  // Gets the layout parameters for this request.
+  // Does not confer ownership.
+  mojo::ui::ViewLayoutParams* layout_params() { return layout_params_.get(); }
+
+  // Gets the layout parameters for this request and takes ownership.
+  mojo::ui::ViewLayoutParamsPtr TakeLayoutParams() {
+    return layout_params_.Pass();
+  }
+
+  // Adds a callback to this layout request.
+  // Must be called before dispatching.
+  void AddCallback(const ViewLayoutCallback& callback);
+
+  // Returns true if the request has callbacks.
+  bool has_callbacks() { return !callbacks_.empty(); }
+
+  // Sends the layout information to each client.
+  // Must be invoked exactly once before destroying the request to prevent
+  // dangling callbacks.
+  void DispatchLayoutInfo(mojo::ui::ViewLayoutInfo* info);
+
+  // True if the request has been issued to the view.
+  // False if it is still pending in the queue.
+  bool issued() const { return issued_; }
+  void set_issued(bool value) { issued_ = value; }
+
+ private:
+  mojo::ui::ViewLayoutParamsPtr layout_params_;
+  std::vector<ViewLayoutCallback> callbacks_;
+  bool was_dispatched_;
+  bool issued_;
+
+  DISALLOW_COPY_AND_ASSIGN(ViewLayoutRequest);
+};
+
+}  // namespace view_manager
+
+#endif  // SERVICES_UI_VIEW_MANAGER_VIEW_LAYOUT_REQUEST_H_