EME: Allow temporary sessions to be removed for ClearKey only.

media/blink/webcontentdecryptionmodulesession_impl.h

Index: media/blink/webcontentdecryptionmodulesession_impl.h
diff --git a/media/blink/webcontentdecryptionmodulesession_impl.h b/media/blink/webcontentdecryptionmodulesession_impl.h
index 9b7cdf2ab43f0504ffa3a09a1b445ae1ae4891d0..d1ec07dfc5d973347366aa26562cc6a5375b16bd 100644
--- a/media/blink/webcontentdecryptionmodulesession_impl.h
+++ b/media/blink/webcontentdecryptionmodulesession_impl.h
@@ -84,6 +84,9 @@ class WebContentDecryptionModuleSessionImpl
   bool has_close_been_called_;
   bool is_closed_;
 
+  // Keep track of whether this is a persistent session or not.
+  bool is_persistent_session_;
+
   base::ThreadChecker thread_checker_;
   // Since promises will live until they are fired, use a weak reference when
   // creating a promise in case this class disappears before the promise