Cast extension private API for ChromeOS system tray.

chrome/browser/extensions/api/cast_devices_private/cast_devices_private_api.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 CHROME_BROWSER_EXTENSIONS_API_CAST_DEVICES_PRIVATE_CAST_DEVICES_PRIVATE_API_H_
+#define CHROME_BROWSER_EXTENSIONS_API_CAST_DEVICES_PRIVATE_CAST_DEVICES_PRIVATE_API_H_
+
+#include <vector>
+
+#include "ash/cast_config_delegate.h"
+#include "base/callback_list.h"
+#include "extensions/browser/browser_context_keyed_api_factory.h"
+#include "extensions/browser/extension_function.h"
+
+namespace extensions {
+
+class CastDeviceUpdateListeners : public BrowserContextKeyedAPI {
+ public:
+  explicit CastDeviceUpdateListeners(content::BrowserContext* context);
+  ~CastDeviceUpdateListeners() override;
+

[Ken Rockot(use gerrit already), 2015/08/14 23:20:09]

Since it seems like this will be fine if created on-demand, can you please
define

static const bool kServiceIsCreatedWithBrowserContext = false;

in this class definition? (see
extensions/browser/browser_context_keyed_api_factory.h for docs in unclear)

[jdufault, 2015/08/15 00:04:52]

Done.

+  // Fetch an instance for the given context.
+  static CastDeviceUpdateListeners* Get(content::BrowserContext* context);
+
+  // Register a function that will be invoked only when a new device update is
+  // available.
+  ash::CastConfigDelegate::DeviceUpdateSubscription RegisterCallback(
+      const ash::CastConfigDelegate::ReceiversAndActivitesCallback& callback);
+
+  // BrowserContextKeyedAPI implementation:
+  static BrowserContextKeyedAPIFactory<CastDeviceUpdateListeners>*
+  GetFactoryInstance();
+
+ private:
+  friend class CastDevicesPrivateUpdateDevicesFunction;  // For NotifyCallbacks.
+  void NotifyCallbacks(
+      const std::vector<ash::CastConfigDelegate::ReceiverAndActivity>& devices);
+
+  base::CallbackList<void(
+      const std::vector<ash::CastConfigDelegate::ReceiverAndActivity>&)>
+      callback_list_;
+
+  friend class BrowserContextKeyedAPIFactory<CastDeviceUpdateListeners>;
+
+  // BrowserContextKeyedAPI implementation:
+  static const char* service_name() { return "CastDeviceUpdateListeners"; }
+
+  DISALLOW_COPY_AND_ASSIGN(CastDeviceUpdateListeners);
+};
+
+// static void updateDeviceState(ReceiverActivity[] devices);
+class CastDevicesPrivateUpdateDevicesFunction : public AsyncExtensionFunction {

[Ken Rockot(use gerrit already), 2015/08/14 23:20:09]

It's preferable for new code to inherit UIThreadExtensionFunction as the base
ExtensionFunction interface now provides a more readable interface for doing
asynchronous work.

See docs in extension_function.h, but basically you implement Run instead of
RunAsync, and you can return a RespondLater() action to indicate that you'll
eventually call Respond().

[jdufault, 2015/08/15 00:04:52]

Done.

+ public:
+  CastDevicesPrivateUpdateDevicesFunction();
+
+ private:
+  ~CastDevicesPrivateUpdateDevicesFunction() override;
+
+  // ExtensionFunction:
+  bool RunAsync() override;
+
+  DECLARE_EXTENSION_FUNCTION("cast.devicesPrivate.updateDevices",
+                             CASTDEVICESPRIVATE_UPDATEDEVICES);
+  DISALLOW_COPY_AND_ASSIGN(CastDevicesPrivateUpdateDevicesFunction);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_CAST_DEVICES_PRIVATE_CAST_DEVICES_PRIVATE_API_H_