Presentation API: reject screen availability observing on Android low ram devices.

chrome/browser/media/router/media_sinks_observer.h

Index: chrome/browser/media/router/media_sinks_observer.h
diff --git a/chrome/browser/media/router/media_sinks_observer.h b/chrome/browser/media/router/media_sinks_observer.h
index 36037edbef12834f727c31b2eadae3c9a33797d6..95c137c9b00d60941366b20a7c62d08c39db023b 100644
--- a/chrome/browser/media/router/media_sinks_observer.h
+++ b/chrome/browser/media/router/media_sinks_observer.h
@@ -35,9 +35,12 @@ class MediaSinksObserver {
 
   const MediaSource& source() const { return source_; }
 
+  bool is_active() const { return is_active_; }
+
  private:
   const MediaSource source_;
   MediaRouter* router_;
+  bool is_active_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSinksObserver);
 };