Stub implementation of Permissions API module.

Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.gypi',
   ],
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
@@ skipping 100 matching lines @@
       'mediastream/RTCSessionDescriptionCallback.idl',
       'mediastream/RTCStatsCallback.idl',
       'mediastream/RTCStatsReport.idl',
       'mediastream/RTCStatsResponse.idl',
       'mediastream/SourceInfo.idl',
       'netinfo/NetworkInformation.idl',
       'notifications/Notification.idl',
       'notifications/NotificationEvent.idl',
       'notifications/NotificationPermissionCallback.idl',
       'performance/WorkerPerformance.idl',
+      'permissions/Permissions.idl',
+      'permissions/PermissionStatus.idl',
       'presentation/Presentation.idl',
       'presentation/PresentationSession.idl',
       'push_messaging/PushEvent.idl',
       'push_messaging/PushManager.idl',
       'push_messaging/PushMessageData.idl',
       'push_messaging/PushRegistration.idl',
       'quota/DeprecatedStorageInfo.idl',
       'quota/DeprecatedStorageQuota.idl',
       'quota/StorageErrorCallback.idl',
       'quota/StorageInfo.idl',
@@ skipping 625 matching lines @@
       'notifications/NotificationPermissionClient.cpp',
       'notifications/NotificationPermissionClient.h',
       'notifications/ServiceWorkerGlobalScopeNotifications.h',
       'notifications/ServiceWorkerRegistrationNotifications.cpp',
       'notifications/ServiceWorkerRegistrationNotifications.h',
       'performance/SharedWorkerPerformance.cpp',
       'performance/WorkerGlobalScopePerformance.cpp',
       'performance/WorkerGlobalScopePerformance.h',
       'performance/WorkerPerformance.cpp',
       'performance/WorkerPerformance.h',
+      'permissions/Permissions.cpp',
+      'permissions/Permissions.h',
+      'permissions/PermissionStatus.cpp',
+      'permissions/PermissionStatus.h',
       'presentation/NavigatorPresentation.cpp',
       'presentation/NavigatorPresentation.h',
       'presentation/Presentation.cpp',
       'presentation/Presentation.h',
       'presentation/PresentationSession.cpp',
       'presentation/PresentationSession.h',
       'push_messaging/NavigatorPushManager.cpp',
       'push_messaging/NavigatorPushManager.h',
       'push_messaging/PushController.cpp',
       'push_messaging/PushController.h',
@@ skipping 354 matching lines @@
       'serviceworkers/CacheTest.cpp',
       'serviceworkers/FetchResponseDataTest.cpp',
       'serviceworkers/RequestTest.cpp',
       'serviceworkers/ResponseTest.cpp',
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }