mus: Make --use-mus-in-renderer the default for --mash.

content/renderer/mus/renderer_window_tree_client.cc

Index: content/renderer/mus/renderer_window_tree_client.cc
diff --git a/content/renderer/mus/renderer_window_tree_client.cc b/content/renderer/mus/renderer_window_tree_client.cc
index 2be8bcf1a00c984291241f1c0156d5f9ddfbc31f..e9827f8c0a65c1fb216981f8c307d6157039e48c 100644
--- a/content/renderer/mus/renderer_window_tree_client.cc
+++ b/content/renderer/mus/renderer_window_tree_client.cc
@@ -27,12 +27,20 @@ RendererWindowTreeClient* RendererWindowTreeClient::Get(int routing_id) {
 
 // static
 void RendererWindowTreeClient::Create(int routing_id) {
-  DCHECK(g_connections.Get().find(routing_id) == g_connections.Get().end());
+  DCHECK(g_connections.Get().find(routing_id) == g_connections.Get().end())
+      << routing_id;
   RendererWindowTreeClient* connection =
       new RendererWindowTreeClient(routing_id);
   g_connections.Get().insert(std::make_pair(routing_id, connection));
 }
 
+// static
+void RendererWindowTreeClient::Destroy(int routing_id) {
+  auto* client = Get(routing_id);
+  if (client)
+    client->DestroySelf();
+}
+
 RendererWindowTreeClient::RendererWindowTreeClient(int routing_id)
     : routing_id_(routing_id), binding_(this) {}