Expose NavigatorHost via Embed() rather than globally.

mojo/public/cpp/application/lazy_interface_ptr.h

Index: mojo/public/cpp/application/lazy_interface_ptr.h
diff --git a/mojo/public/cpp/application/lazy_interface_ptr.h b/mojo/public/cpp/application/lazy_interface_ptr.h
index 62d0ae9f6ee32d414ec63ce69f9b4362b5dd682b..00de7525c6bb877b1d46fe520fbe2623dac8c45d 100644
--- a/mojo/public/cpp/application/lazy_interface_ptr.h
+++ b/mojo/public/cpp/application/lazy_interface_ptr.h
@@ -15,10 +15,17 @@ namespace mojo {
 template<typename Interface>
 class LazyInterfacePtr : InterfacePtr<Interface> {
  public:
+  LazyInterfacePtr() : service_provider_(NULL) {}
+
   LazyInterfacePtr(ServiceProvider* service_provider)
       : service_provider_(service_provider) {
   }
 
+  void set_service_provider(ServiceProvider* service_provider) {

[darin (slow to review), 2014/09/04 23:22:18]

you probably want to make sure InterfacePtr<Interface>::get() would return null,
right? that way someone doesn't try to change the service provider after the
ConnectToService was called.

this method could also be called Initialize. not sure if you want to go there.
it might help re-inforce the idea that it can only be called once, and that it
is an alternative to the 1-arg ctor.

[Aaron Boodman, 2014/09/05 04:22:34]

I decided to just reset the InterfaceProvider when this is called, so that it
can be called multiple times. Does that work for you?

+    DCHECK(!service_provider_);
+    service_provider_ = service_provider;
+  }
+
   Interface* get() const {
     if (!InterfacePtr<Interface>::get()) {
       mojo::ConnectToService<Interface>(