Use instance name to uniquify renderers.

content/browser/renderer_host/render_widget_host_view_mus.cc

Index: content/browser/renderer_host/render_widget_host_view_mus.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_mus.cc b/content/browser/renderer_host/render_widget_host_view_mus.cc
index 9ddef3eee0a7a456731d52d5f98dab5bb39af908..31572664a2949bdecf944d76fb8354f856670346 100644
--- a/content/browser/renderer_host/render_widget_host_view_mus.cc
+++ b/content/browser/renderer_host/render_widget_host_view_mus.cc
@@ -38,9 +38,10 @@ RenderWidgetHostViewMus::RenderWidgetHostViewMus(mus::Window* parent_window,
 
   // Connect to the renderer, pass it a WindowTreeClient interface request
   // and embed that client inside our mus window.
-  std::string url = GetMojoApplicationInstanceURL(host_->GetProcess());
+  mojo::Identity identity = GetMojoIdentity(host_->GetProcess());
   mojom::RenderWidgetWindowTreeClientFactoryPtr factory;
-  MojoShellConnection::Get()->GetConnector()->ConnectToInterface(url, &factory);
+  MojoShellConnection::Get()->GetConnector()->ConnectToInterface(
+      identity, &factory);
 
   mus::mojom::WindowTreeClientPtr window_tree_client;
   factory->CreateWindowTreeClientForRenderWidget(