Allow gaming_seat to use ozone gamepad as back-end

components/exo/gaming_seat.h

Index: components/exo/gaming_seat.h
diff --git a/components/exo/gaming_seat.h b/components/exo/gaming_seat.h
index 40e44ae33352eeb4cf86c473177ce37d6e52c548..2c9787f08a9cb23e856b28fa1e0a4748e277d505 100644
--- a/components/exo/gaming_seat.h
+++ b/components/exo/gaming_seat.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 
+#include "base/containers/flat_map.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
@@ -17,6 +18,10 @@
 #include "device/gamepad/gamepad_data_fetcher.h"
 #include "ui/aura/client/focus_change_observer.h"
 
+#if defined(USE_OZONE_GAMEPAD)
+#include "ui/events/ozone/gamepad/gamepad_observer.h"
+#endif
+
 namespace exo {
 class GamingSeatDelegate;
 class GamepadDelegate;
@@ -24,29 +29,43 @@ class GamepadDelegate;
 using CreateGamepadDataFetcherCallback =
     base::Callback<std::unique_ptr<device::GamepadDataFetcher>()>;
 
-// This class represents one gaming seat, it uses a background thread
-// for polling gamepad devices and notifies the corresponding GampadDelegate of
-// any changes.
-class GamingSeat : public WMHelper::FocusObserver {
+// TODO(jkwang): always use ozone_gamepad when ozone is default for all Chrome
+// OS builds. https://crbug.com/717246
+// This class represents one gaming seat. It uses /device/gamepad or
+// ozone/gamepad as backend and notifies corresponding GamepadDelegate of any
+// gamepad changes.
+class GamingSeat : public WMHelper::FocusObserver
+#if defined(USE_OZONE_GAMEPAD)
+                   ,
+                   public ui::GamepadObserver
+#endif
+{
  public:
-  // This class will post tasks to invoke the delegate on the thread runner
-  // which is associated with the thread that is creating this instance.
+  // This class will monitor gamepad connection changes and manage gamepad
+  // returned by gaming_seat_delegate.
   GamingSeat(GamingSeatDelegate* gaming_seat_delegate,
              base::SingleThreadTaskRunner* polling_task_runner);
 
-  // Allows test cases to specify a CreateGamepadDataFetcherCallback that
-  // overrides the default GamepadPlatformDataFetcher.
-  GamingSeat(GamingSeatDelegate* gaming_seat_delegate,
-             base::SingleThreadTaskRunner* polling_task_runner,
-             CreateGamepadDataFetcherCallback create_fetcher_callback);
-
   ~GamingSeat() override;
 
-  // Overridden WMHelper::FocusObserver:
+  // Overridden from WMHelper::FocusObserver:
   void OnWindowFocused(aura::Window* gained_focus,
                        aura::Window* lost_focus) override;
 
+#if defined(USE_OZONE_GAMEPAD)
+  // Overridden from ui::GamepadObserver:
+  void OnGamepadDevicesUpdated() override;
+  void OnGamepadEvent(const ui::GamepadEvent& event) override;
+#endif
+
  private:
+  // The delegate that handles gamepad_added.
+  GamingSeatDelegate* const delegate_;
+
+#if defined(USE_OZONE_GAMEPAD)
+  // Contains the delegate for each gamepad device.
+  base::flat_map<int, GamepadDelegate*> gamepads_;
+#else
   class ThreadSafeGamepadChangeFetcher;
 
   // Processes updates of gamepad data and passes changes on to delegate.
@@ -56,9 +75,6 @@ class GamingSeat : public WMHelper::FocusObserver {
   // polling thread.
   scoped_refptr<ThreadSafeGamepadChangeFetcher> gamepad_change_fetcher_;
 
-  // The delegate that handles gamepad_added.
-  GamingSeatDelegate* const delegate_;
-
   // The delegate instances that all other events are dispatched to.
   GamepadDelegate* gamepad_delegates_[device::Gamepads::kItemsLengthCap];
 
@@ -66,9 +82,10 @@ class GamingSeat : public WMHelper::FocusObserver {
   device::Gamepads pad_state_;
 
   // ThreadChecker for the origin thread.
-  base::ThreadChecker thread_checker_;
+  THREAD_CHECKER(thread_checker_);
 
   base::WeakPtrFactory<GamingSeat> weak_ptr_factory_;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(GamingSeat);
 };