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..78c968ad8339eeaa4e84a25ef6d694ad5dc601f5 100644
--- a/mojo/shell/ui_service_loader_android.cc
+++ b/mojo/shell/ui_service_loader_android.cc
@@ -18,7 +18,9 @@ class UIServiceLoader::UILoader {
   void LoadService(ServiceManager* manager,
                    const GURL& url,
                    ScopedMessagePipeHandle shell_handle) {
-    loader_->LoadService(manager, url, shell_handle.Pass());
+    scoped_refptr<LoadServiceCallbacks> callbacks(
+        new ServiceLoader::SimpleLoadServiceCallbacks(shell_handle.Pass()));
+    loader_->LoadService(manager, url, callbacks);
   }
 
   void OnServiceError(ServiceManager* manager, const GURL& url) {
@@ -42,9 +44,14 @@ UIServiceLoader::~UIServiceLoader() {
       base::Bind(&UIServiceLoader::ShutdownOnUIThread, base::Unretained(this)));
 }
 
-void UIServiceLoader::LoadService(ServiceManager* manager,
-                                  const GURL& url,
-                                  ScopedMessagePipeHandle shell_handle) {
+void UIServiceLoader::LoadService(
+    ServiceManager* manager,
+    const GURL& url,
+    scoped_refptr<LoadServiceCallbacks> callbacks) {
+  ScopedMessagePipeHandle shell_handle = callbacks->RegisterApplication();
+  if (!shell_handle.is_valid()) {
+    return;
+  }
   context_->ui_loop()->PostTask(
       FROM_HERE,
       base::Bind(
@@ -52,7 +59,7 @@ void UIServiceLoader::LoadService(ServiceManager* manager,
           base::Unretained(this),
           manager,
           url,
-          base::Owned(new ScopedMessagePipeHandle(shell_handle.Pass()))));
+          shell_handle.Pass()));
 }
 
 void UIServiceLoader::OnServiceError(ServiceManager* manager, const GURL& url) {
@@ -67,10 +74,10 @@ void UIServiceLoader::OnServiceError(ServiceManager* manager, const GURL& url) {
 void UIServiceLoader::LoadServiceOnUIThread(
     ServiceManager* manager,
     const GURL& url,
-    ScopedMessagePipeHandle* shell_handle) {
+    ScopedMessagePipeHandle shell_handle) {
   if (!ui_loader_)
     ui_loader_ = new UILoader(loader_.get());
-  ui_loader_->LoadService(manager, url, shell_handle->Pass());
+  ui_loader_->LoadService(manager, url, shell_handle.Pass());
 }
 
 void UIServiceLoader::OnServiceErrorOnUIThread(ServiceManager* manager,