【粗读webrtc】创建mediaengine

• 本人也写过自己mediaengine
• 现在看下webrtc是怎么做的
  
• O:\WEBRWTCSTORE\webrtc-checkout\src\media\engine\webrtc_media_engine.h

MediaEngineInterface

• mediaengine 是一个 MediaEngineInterface

// MediaEngineInterface is an abstraction of a media engine which can be
// subclassed to support different media componentry backends.
// It supports voice and video operations in the same class to facilitate
// proper synchronization between both media types.
class