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

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 135a0ccca171dfc7600b12ebada6104a8afccd0a..1f4fc7e53d5812e68005502dfe91ceef32d3c5e0 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -331,6 +331,7 @@
 #include "chrome/browser/media/cast_remoting_connector.h"
 #include "chrome/browser/media/router/media_router_feature.h"
 #include "chrome/browser/media/router/presentation_service_delegate_impl.h"
+#include "chrome/browser/media/router/receiver_presentation_service_delegate_impl.h"
 #endif
 
 #if defined(ENABLE_WAYLAND_SERVER)
@@ -3082,6 +3083,15 @@ ChromeContentBrowserClient::GetPresentationServiceDelegate(
       content::WebContents* web_contents) {
 #if defined(ENABLE_MEDIA_ROUTER)
   if (media_router::MediaRouterEnabled(web_contents->GetBrowserContext())) {
+    // ReceiverPresentationServiceDelegateImpl exists only for WebContents
+    // created for offscreen presentations. The WebContents must belong to
+    // an incognito profile. WebContents cannot be a presentation receiver and
+    // a presentation controller.
+    if (auto* impl = media_router::ReceiverPresentationServiceDelegateImpl::
+            FromWebContents(web_contents)) {
+      DCHECK(web_contents->GetBrowserContext()->IsOffTheRecord());
+      return impl;
+    }
     return media_router::PresentationServiceDelegateImpl::
         GetOrCreateForWebContents(web_contents);
   }