[Presentation API] 1-UA: send message between controller and receiver page

third_party/WebKit/public/platform/modules/presentation/WebPresentationReceiver.h

Index: third_party/WebKit/public/platform/modules/presentation/WebPresentationReceiver.h
diff --git a/third_party/WebKit/public/platform/modules/presentation/WebPresentationReceiver.h b/third_party/WebKit/public/platform/modules/presentation/WebPresentationReceiver.h
index 6757410af11f2ccfb482eca21b73622c0fed2e63..51166ff6909a863429825b4ad935003e59622947 100644
--- a/third_party/WebKit/public/platform/modules/presentation/WebPresentationReceiver.h
+++ b/third_party/WebKit/public/platform/modules/presentation/WebPresentationReceiver.h
@@ -6,13 +6,12 @@
 #define WebPresentationReceiver_h
 
 #include "public/platform/WebCommon.h"
+#include "public/platform/modules/presentation/WebPresentationClient.h"
 
 namespace blink {
 
-class WebPresentationConnectionClient;
-
 // The delegate Blink provides to WebPresentationReceiverClient in order to get updates.
-class BLINK_PLATFORM_EXPORT WebPresentationReceiver {
+class BLINK_PLATFORM_EXPORT WebPresentationReceiver : public WebPresentationMessageObserver {
 public:
     virtual ~WebPresentationReceiver() = default;