[Presentation API] 1-UA presentation support + presenter APIs.

chrome/browser/extensions/api/tab_capture/offscreen_presentation.cc

Index: chrome/browser/extensions/api/tab_capture/offscreen_presentation.cc
diff --git a/chrome/browser/extensions/api/tab_capture/offscreen_presentation.cc b/chrome/browser/extensions/api/tab_capture/offscreen_presentation.cc
index f83a6f6d1520c8672001a0f5d7656cbf6467fad0..d0aec3101e85d07a7e6b2db2aa7ab9f193ab051a 100644
--- a/chrome/browser/extensions/api/tab_capture/offscreen_presentation.cc
+++ b/chrome/browser/extensions/api/tab_capture/offscreen_presentation.cc
@@ -8,6 +8,7 @@
 
 #include "base/bind.h"
 #include "chrome/browser/extensions/api/tab_capture/tab_capture_registry.h"
+#include "chrome/browser/media/router/receiver_presentation_service_delegate_impl.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/web_contents_sizer.h"
 #include "content/public/browser/render_widget_host_view.h"
@@ -201,11 +202,10 @@ void OffscreenPresentation::Start(const gfx::Size& initial_size) {
   // automatically unmuted, but will be captured into the MediaStream.
   presentation_web_contents_->SetAudioMuted(true);
 
-  // TODO(imcheng): If |presentation_id_| is not empty, register it with the
-  // PresentationRouter.  http://crbug.com/513859
   if (!presentation_id_.empty()) {
-    NOTIMPLEMENTED()
-        << "Register with PresentationRouter, id=" << presentation_id_;
+    // Register the offscreen tab as the receiver of the offscreen presentation.
+    media_router::ReceiverPresentationServiceDelegateImpl::CreateForWebContents(
+        presentation_web_contents_.get(), presentation_id_);
   }
 
   // Navigate to the initial URL of the presentation.