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content / public / browser / media_keys_listener_manager.h [blame]
// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_PUBLIC_BROWSER_MEDIA_KEYS_LISTENER_MANAGER_H_
#define CONTENT_PUBLIC_BROWSER_MEDIA_KEYS_LISTENER_MANAGER_H_
#include "base/unguessable_token.h"
#include "content/common/content_export.h"
#include "ui/base/accelerators/media_keys_listener.h"
#include "ui/events/keycodes/keyboard_codes.h"
namespace content {
// The browser listens for media keys and uses them to control the active media
// session. However, there are cases where this behavior is undesirable, for
// example when an extension wants to handle media key presses instead. This
// class provides an interface for code outside of content (e.g. extensions) to
// receive global media key input instead of allowing the browser to use it to
// control the active session.
class MediaKeysListenerManager {
public:
// Returns the singleton instance.
CONTENT_EXPORT static MediaKeysListenerManager* GetInstance();
// Returns true if the MediaKeysListenerManager is enabled, taking OS and
// feature flags into account.
CONTENT_EXPORT static bool IsMediaKeysListenerManagerEnabled();
// Start listening for a given media key. Returns true if the listener
// successfully started listening for the key. This will prevent the
// HardwareKeyMediaController from also handling the specified key.
// Note: Delegates *must* call |StopWatchingMediaKey()| for each key code
// they're listening to before destruction in order to prevent the
// MediaKeysListenerManager from holding invalid pointers.
// For instanced web apps that are beginning to listen for media keys,
// the request_id of the media session that is associated with the web app
// needs to be provided via |web_app_request_id|. Otherwise, this param can
// be ignored.
virtual bool StartWatchingMediaKey(ui::KeyboardCode key_code,
ui::MediaKeysListener::Delegate* delegate,
base::UnguessableToken web_app_request_id =
base::UnguessableToken::Null()) = 0;
// Stop listening for a given media key. This will free the key to be handled
// by the HardwareKeyMediaController. Delegates must stop watching all keys
// before they are destroyed in order to prevent the MediaKeysListenerManager
// from holding invalid pointers.
// For instanced web apps that are beginning to listen for media keys,
// the request_id of the media session that is associated with the web app
// needs to be provided via |web_app_request_id|. Otherwise, this param can
// be ignored.
virtual void StopWatchingMediaKey(ui::KeyboardCode key_code,
ui::MediaKeysListener::Delegate* delegate,
base::UnguessableToken web_app_request_id =
base::UnguessableToken::Null()) = 0;
// Prevent the browser from using media key presses to control the active
// media session. This allows a caller to prevent the media key handling
// without registering to receive the key events. Note that this does not
// prevent callers of |StartWatchingMediaKey()| from receiving media key
// events. This does not need to be called if |StartWatchingMediaKey()| is
// used, since |StartWatchingMediaKey()| will automatically prevent the
// browser from using the media key presses.
virtual void DisableInternalMediaKeyHandling() = 0;
// Allows the browser to use media key presses to control the active media.
// Only needs to be called if a call to |DisableInternalMediaKeyHandling()|
// has been made.
virtual void EnableInternalMediaKeyHandling() = 0;
protected:
virtual ~MediaKeysListenerManager();
};
} // namespace content
#endif // CONTENT_PUBLIC_BROWSER_MEDIA_KEYS_LISTENER_MANAGER_H_