[Presentation API] (MR side) 1-UA: notify receiver page when receiver connection becomes available

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 23b85095b8c6428f195775fae766ca2aa56ea70d..17c47514c887f8c303ce7ae1c8e59f2d9cd21c0e 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -323,6 +323,7 @@
 #if defined(ENABLE_MEDIA_ROUTER)
 #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)
@@ -3009,6 +3010,13 @@ ChromeContentBrowserClient::GetPresentationServiceDelegate(
       content::WebContents* web_contents) {
 #if defined(ENABLE_MEDIA_ROUTER)
   if (media_router::MediaRouterEnabled(web_contents->GetBrowserContext())) {
+    // ReceiverPresentationServiceDelegateImpl are for WebContents created for
+    // offscreen presentations. The WebContents is from an incognito profile.
+    if (auto* impl = media_router::ReceiverPresentationServiceDelegateImpl::
+            FromWebContents(web_contents)) {
+      DCHECK(web_contents->GetBrowserContext()->IsOffTheRecord());
+      return impl;
+    }
     return media_router::PresentationServiceDelegateImpl::
         GetOrCreateForWebContents(web_contents);
   }