Separate out event-targeting logic in EventDispatcher to EventTargeter.

services/ui/ws/event_targeter.h

+// Copyright 2017 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_WS_EVENT_TARGETER_H_
+#define SERVICES_UI_WS_EVENT_TARGETER_H_
+
+#include "base/macros.h"
+
+namespace gfx {
+class Point;
+}
+
+namespace ui {
+class LocatedEvent;
+
+namespace ws {
+struct DeepestWindow;
+class EventDispatcherDelegate;
+class ModalWindowController;
+class ServerWindow;
+
+// Keeps track of state associated with an active pointer.
+struct PointerTarget {
+  PointerTarget()
+      : window(nullptr),
+        is_mouse_event(false),
+        in_nonclient_area(false),
+        is_pointer_down(false) {}
+
+  // The target window, which may be null. null is used in two situations:
+  // when there is no valid window target, or there was a target but the
+  // window is destroyed before a corresponding release/cancel.
+  ServerWindow* window;
+
+  bool is_mouse_event;
+
+  // Did the pointer event start in the non-client area.
+  bool in_nonclient_area;
+
+  bool is_pointer_down;
+};
+
+// Finds the PointerTarget for an event or the DeepestWindow for a location.
+class EventTargeter {
+ public:
+  EventTargeter(EventDispatcherDelegate* event_dispatcher_delegate,
+                ModalWindowController* modal_window_controller);
+  ~EventTargeter();
+
+  // Returns a PointerTarget for the supplied |event|. If there is no valid
+  // event target for the specified location |window| in the returned value is
+  // null.
+  PointerTarget PointerTargetForEvent(const ui::LocatedEvent& event);
+
+  // Returns a DeepestWindow for the supplied |location|. If there is no valid
+  // root window, |window| in the returned value is null.
+  DeepestWindow FindDeepestVisibleWindowForEvents(const gfx::Point& location);
+
+ private:
+  EventDispatcherDelegate* event_dispatcher_delegate_;
+  ModalWindowController* modal_window_controller_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventTargeter);
+};
+
+}  // namespace ws
+}  // namespace ui
+
+#endif  // SERVICES_UI_WS_EVENT_TARGETER_H_