Presentation API: add settings for presentation.receiver being exposed.

content/public/common/web_preferences.h

Index: content/public/common/web_preferences.h
diff --git a/content/public/common/web_preferences.h b/content/public/common/web_preferences.h
index a82de688673d85d7508fd3b1a3ab8c4950aaf5cb..e325e5077c136d193eceb02491d2e72e7a07d432 100644
--- a/content/public/common/web_preferences.h
+++ b/content/public/common/web_preferences.h
@@ -265,6 +265,9 @@ struct CONTENT_EXPORT WebPreferences {
   // If enabled, disabled video track when the video is in the background.
   bool background_video_track_optimization_enabled;
 
+  // Whether it is a presentation receiver.
+  bool presentation_receiver;
+
   // We try to keep the default values the same as the default values in
   // chrome, except for the cases where it would require lots of extra work for
   // the embedder to use the same default value.