fix(FEC-7970): Change media from DRM to DRM is not working (#202)

Remove destroy from DrmProtocol interface since it has no meaning and we're overriding the old protocol with the new protocol on change media.

flow-typed/interfaces/drm-protocol.js

@@ -2,5 +2,4 @@
 declare interface IDrmProtocol {
   static canPlayDrm(drmData: Array<Object>): boolean;
   static setDrmPlayback(...any): void;
-  static destroy(): void;
 }

src/drm/base-drm-protocol.js

@@ -17,7 +17,4 @@ export default class BaseDrmProtocol implements IDrmProtocol {
   static setDrmPlayback(...args): void {
     throw new Error(Error.Severity.CRITICAL, Error.Category.PLAYER, Error.Code.RUNTIME_ERROR_METHOD_NOT_IMPLEMENTED, 'static setDrmPlayback');
   }
-
-  static destroy(): void {
-  }
 }

src/engines/html5/media-source/adapters/native-adapter.js

@@ -281,10 +281,6 @@ export default class NativeAdapter extends BaseMediaSourceAdapter {
         clearInterval(this._liveDurationChangeInterval);
         this._liveDurationChangeInterval = null;
       }
-      if (NativeAdapter._drmProtocol) {
-        NativeAdapter._drmProtocol.destroy();
-        NativeAdapter._drmProtocol = null;
-      }
     });
   }