[PresentationAPI] Implementing start/joinSession from WebPresentationClient to PresentationService.

content/browser/presentation/presentation_service_impl.cc

Index: content/browser/presentation/presentation_service_impl.cc
diff --git a/content/browser/presentation/presentation_service_impl.cc b/content/browser/presentation/presentation_service_impl.cc
index 02e2773080adf269686f341838ed690469a7c15e..4a1db13ea7a41d8e8d79981ecfe079f8b731a41a 100644
--- a/content/browser/presentation/presentation_service_impl.cc
+++ b/content/browser/presentation/presentation_service_impl.cc
@@ -99,6 +99,20 @@ void PresentationServiceImpl::OnScreenAvailabilityListenerRemoved() {
   NOTIMPLEMENTED();
 }
 
+void PresentationServiceImpl::StartSession(
+    const mojo::String& presentation_url,
+    const mojo::String& presentation_id,
+    const NewSessionMojoCallback& callback) {
+  NOTIMPLEMENTED();
+}
+
+void PresentationServiceImpl::JoinSession(
+    const mojo::String& presentation_url,
+    const mojo::String& presentation_id,
+    const NewSessionMojoCallback& callback) {
+  NOTIMPLEMENTED();
+}
+
 void PresentationServiceImpl::DidNavigateAnyFrame(
     content::RenderFrameHost* render_frame_host,
     const content::LoadCommittedDetails& details,