First cut at "content handling" support in Mojo.

mojo/shell/ui_service_loader_android.cc

Index: mojo/shell/ui_service_loader_android.cc
diff --git a/mojo/shell/ui_service_loader_android.cc b/mojo/shell/ui_service_loader_android.cc
index 3960858c2f73ad165f980c1ebd6799c3e802d4ad..e2f77464bf8d05fb753809263b1740c08d975715 100644
--- a/mojo/shell/ui_service_loader_android.cc
+++ b/mojo/shell/ui_service_loader_android.cc
@@ -15,10 +15,12 @@ class UIServiceLoader::UILoader {
   explicit UILoader(ServiceLoader* loader) : loader_(loader) {}
   ~UILoader() {}
 
-  void LoadService(ServiceManager* manager,
-                   const GURL& url,
-                   ScopedMessagePipeHandle shell_handle) {
-    loader_->LoadService(manager, url, shell_handle.Pass());
+  void Load(ServiceManager* manager,
+            const GURL& url,
+            ScopedMessagePipeHandle shell_handle) {
+    scoped_refptr<LoadCallbacks> callbacks(
+        new ServiceLoader::SimpleLoadCallbacks(shell_handle.Pass()));
+    loader_->Load(manager, url, callbacks);
   }
 
   void OnServiceError(ServiceManager* manager, const GURL& url) {
@@ -42,17 +44,20 @@ UIServiceLoader::~UIServiceLoader() {
       base::Bind(&UIServiceLoader::ShutdownOnUIThread, base::Unretained(this)));
 }
 
-void UIServiceLoader::LoadService(ServiceManager* manager,
-                                  const GURL& url,
-                                  ScopedMessagePipeHandle shell_handle) {
+void UIServiceLoader::Load(ServiceManager* manager,
+                           const GURL& url,
+                           scoped_refptr<LoadCallbacks> callbacks) {
+  ScopedMessagePipeHandle shell_handle = callbacks->RegisterApplication();
+  if (!shell_handle.is_valid())
+    return;
   context_->ui_loop()->PostTask(
       FROM_HERE,
-      base::Bind(
-          &UIServiceLoader::LoadServiceOnUIThread,
-          base::Unretained(this),
-          manager,
-          url,
-          base::Owned(new ScopedMessagePipeHandle(shell_handle.Pass()))));
+      base::Bind(&UIServiceLoader::LoadOnUIThread,
+                 base::Unretained(this),
+                 manager,
+                 url,
+                 base::Owned(
+                     new ScopedMessagePipeHandle(shell_handle.Pass()))));
 }
 
 void UIServiceLoader::OnServiceError(ServiceManager* manager, const GURL& url) {
@@ -64,13 +69,12 @@ void UIServiceLoader::OnServiceError(ServiceManager* manager, const GURL& url) {
                  url));
 }
 
-void UIServiceLoader::LoadServiceOnUIThread(
-    ServiceManager* manager,
-    const GURL& url,
-    ScopedMessagePipeHandle* shell_handle) {
+void UIServiceLoader::LoadOnUIThread(ServiceManager* manager,
+                                     const GURL& url,
+                                     ScopedMessagePipeHandle* shell_handle) {
   if (!ui_loader_)
     ui_loader_ = new UILoader(loader_.get());
-  ui_loader_->LoadService(manager, url, shell_handle->Pass());
+  ui_loader_->Load(manager, url, shell_handle->Pass());
 }
 
 void UIServiceLoader::OnServiceErrorOnUIThread(ServiceManager* manager,