[Blink, RemotePlayback] Dismissing the dialog rejects with NotAllowedError.

third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h

Index: third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h
diff --git a/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h b/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h
index ac7639ab8c95cc4dd834bfa6a9f3f0f7e486958c..88fba79d7926b0639116f2f8cba14f416c97618e 100644
--- a/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h
+++ b/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h
@@ -8,6 +8,7 @@
 #include "bindings/core/v8/ActiveScriptWrappable.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "core/events/EventTarget.h"
+#include "modules/ModulesExport.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/modules/remoteplayback/WebRemotePlaybackClient.h"
 #include "public/platform/modules/remoteplayback/WebRemotePlaybackState.h"
@@ -22,7 +23,7 @@ class LocalFrame;
 class RemotePlaybackAvailability;
 class ScriptPromiseResolver;
 
-class RemotePlayback final
+class MODULES_EXPORT RemotePlayback final
     : public EventTargetWithInlineData
     , public ActiveScriptWrappable
     , private WebRemotePlaybackClient {
@@ -48,6 +49,8 @@ public:
     DECLARE_VIRTUAL_TRACE();
 
 private:
+    friend class RemotePlaybackTest;
+
     explicit RemotePlayback(HTMLMediaElement&);
 
     // WebRemotePlaybackClient implementation.