Add creation of ServiceManager to Content (2nd try)

mojo/service_manager/service_loader.h

Index: mojo/service_manager/service_loader.h
diff --git a/mojo/service_manager/service_loader.h b/mojo/service_manager/service_loader.h
index 7da0540d427482fe39871aae8f2b31ffb6aec88a..6d5be9a8aa618cd1c499808726e8505f4e9fb253 100644
--- a/mojo/service_manager/service_loader.h
+++ b/mojo/service_manager/service_loader.h
@@ -6,6 +6,7 @@
 #define MOJO_SERVICE_MANAGER_SERVICE_LOADER_H_
 
 #include "mojo/public/shell/shell.mojom.h"
+#include "mojo/service_manager/service_manager_export.h"
 #include "url/gurl.h"
 
 namespace mojo {
@@ -14,12 +15,14 @@ class ServiceManager;
 
 // Interface to allowing default loading behavior to be overridden for a
 // specific url.
-class ServiceLoader {
+class MOJO_SERVICE_MANAGER_EXPORT ServiceLoader {
  public:
   virtual ~ServiceLoader() {};
   virtual void LoadService(ServiceManager* manager,
                            const GURL& url,
                            ScopedShellHandle service_handle) = 0;
+  virtual void OnServiceError(ServiceManager* manager, const GURL& url) = 0;
+
  protected:
   ServiceLoader() {}
 };