Simplify use of ContentDecryptionModuleResult with promises

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 397 matching lines @@
       'device_orientation/DeviceOrientationInspectorAgent.cpp',
       'device_orientation/DeviceOrientationInspectorAgent.h',
       'device_orientation/DeviceRotationRate.cpp',
       'device_orientation/DeviceRotationRate.h',
       'donottrack/NavigatorDoNotTrack.cpp',
       'donottrack/NavigatorDoNotTrack.h',
       'encoding/TextDecoder.cpp',
       'encoding/TextDecoder.h',
       'encoding/TextEncoder.cpp',
       'encoding/TextEncoder.h',
+      'encryptedmedia/ContentDecryptionModuleResultPromise.cpp',
+      'encryptedmedia/ContentDecryptionModuleResultPromise.h',
       'encryptedmedia/HTMLMediaElementEncryptedMedia.cpp',
       'encryptedmedia/HTMLMediaElementEncryptedMedia.h',
       'encryptedmedia/MediaEncryptedEvent.cpp',
       'encryptedmedia/MediaEncryptedEvent.h',
       'encryptedmedia/MediaKeyMessageEvent.cpp',
       'encryptedmedia/MediaKeyMessageEvent.h',
       'encryptedmedia/MediaKeySession.cpp',
       'encryptedmedia/MediaKeySession.h',
       'encryptedmedia/MediaKeySystemAccess.cpp',
       'encryptedmedia/MediaKeySystemAccess.h',
       'encryptedmedia/MediaKeys.cpp',
       'encryptedmedia/MediaKeys.h',
       'encryptedmedia/MediaKeysClient.h',
       'encryptedmedia/MediaKeysController.cpp',
       'encryptedmedia/MediaKeysController.h',
       'encryptedmedia/NavigatorRequestMediaKeySystemAccess.cpp',
       'encryptedmedia/NavigatorRequestMediaKeySystemAccess.h',
-      'encryptedmedia/SimpleContentDecryptionModuleResult.cpp',
-      'encryptedmedia/SimpleContentDecryptionModuleResult.h',
+      'encryptedmedia/SimpleContentDecryptionModuleResultPromise.cpp',
+      'encryptedmedia/SimpleContentDecryptionModuleResultPromise.h',
       'filesystem/DOMFilePath.cpp',
       'filesystem/DOMFilePath.h',
       'filesystem/DOMFileSystem.cpp',
       'filesystem/DOMFileSystem.h',
       'filesystem/DOMFileSystemBase.cpp',
       'filesystem/DOMFileSystemBase.h',
       'filesystem/DOMFileSystemSync.cpp',
       'filesystem/DOMFileSystemSync.h',
       'filesystem/DOMWindowFileSystem.cpp',
       'filesystem/DOMWindowFileSystem.h',
@@ skipping 608 matching lines @@
       'serviceworkers/CacheTest.cpp',
       'serviceworkers/FetchResponseDataTest.cpp',
       'serviceworkers/RequestTest.cpp',
       'serviceworkers/ResponseTest.cpp',
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }