First cut at "content handling" support in Mojo.

mojo/shell/context.cc

Index: mojo/shell/context.cc
diff --git a/mojo/shell/context.cc b/mojo/shell/context.cc
index 159e3230d5236cac5a603e8d8ead01ecc935dbf0..91d8e9a26041b6b39bdeef6c2ae116a59eaee69e 100644
--- a/mojo/shell/context.cc
+++ b/mojo/shell/context.cc
@@ -69,10 +69,14 @@ class Context::NativeViewportServiceLoader : public ServiceLoader {
   virtual ~NativeViewportServiceLoader() {}
 
  private:
-  virtual void LoadService(ServiceManager* manager,
-                           const GURL& url,
-                           ScopedMessagePipeHandle shell_handle) OVERRIDE {
-    app_.reset(services::CreateNativeViewportService(shell_handle.Pass()));
+  virtual void LoadService(
+      ServiceManager* manager,
+      const GURL& url,
+      scoped_refptr<LoadServiceCallbacks> callbacks) OVERRIDE {
+    ScopedMessagePipeHandle shell_handle = callbacks->RegisterApplication();
+    if (shell_handle.is_valid()) {
+      app_.reset(services::CreateNativeViewportService(shell_handle.Pass()));
+    }
   }
 
   virtual void OnServiceError(ServiceManager* manager,
@@ -97,9 +101,13 @@ Context::Context()
   else
     runner_factory.reset(new InProcessDynamicServiceRunnerFactory());
 
+  DynamicServiceLoader* dynamic_service_loader =
+      new DynamicServiceLoader(this, runner_factory.Pass());
+  dynamic_service_loader->set_content_handler(
+      "text/plain", GURL("mojo://mojo_content_handler_demo/"));
   service_manager_.set_default_loader(
-      scoped_ptr<ServiceLoader>(
-          new DynamicServiceLoader(this, runner_factory.Pass())));
+      scoped_ptr<ServiceLoader>(dynamic_service_loader));
+
   // The native viewport service synchronously waits for certain messages. If we
   // don't run it on its own thread we can easily deadlock. Long term native
   // viewport should run its own process so that this isn't an issue.