Move content's shell connections to the IO thread

services/shell/public/cpp/lib/interface_provider.cc

Index: services/shell/public/cpp/lib/interface_provider.cc
diff --git a/services/shell/public/cpp/lib/interface_provider.cc b/services/shell/public/cpp/lib/interface_provider.cc
index 209d356ac476bb6a79d8cfc51f389500c8b297b7..77fb6f168eb12deda03d46d3aca3aafc8c5e5b4f 100644
--- a/services/shell/public/cpp/lib/interface_provider.cc
+++ b/services/shell/public/cpp/lib/interface_provider.cc
@@ -4,11 +4,40 @@
 
 #include "services/shell/public/cpp/interface_provider.h"
 
+#include "base/macros.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
 namespace shell {
 
+namespace {
+
+class ForwardingInterfaceProvider : public mojom::InterfaceProvider {
+ public:
+  ForwardingInterfaceProvider(
+      const shell::InterfaceProvider::ForwardCallback& callback,
+      mojom::InterfaceProviderRequest request)
+      : callback_(callback), binding_(this, std::move(request)) {}
+  ~ForwardingInterfaceProvider() override {}
+
+ private:
+  // mojom::InterfaceProvider:
+  void GetInterface(const mojo::String& interface_name,
+                    mojo::ScopedMessagePipeHandle request_handle) override {
+    callback_.Run(interface_name, std::move(request_handle));
+  }
+
+  shell::InterfaceProvider::ForwardCallback callback_;
+  mojo::StrongBinding<mojom::InterfaceProvider> binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(ForwardingInterfaceProvider);
+};
+
+}  // namespace
+
 InterfaceProvider::InterfaceProvider() : weak_factory_(this) {
   pending_request_ = GetProxy(&interface_provider_);
 }
+
 InterfaceProvider::~InterfaceProvider() {}
 
 void InterfaceProvider::Bind(mojom::InterfaceProviderPtr interface_provider) {
@@ -17,6 +46,13 @@ void InterfaceProvider::Bind(mojom::InterfaceProviderPtr interface_provider) {
                       interface_provider.PassInterface());
 }
 
+void InterfaceProvider::Forward(const ForwardCallback& callback) {
+  DCHECK(pending_request_.is_pending());
+
+  // Owns itself.
+  new ForwardingInterfaceProvider(callback, std::move(pending_request_));
+}
+
 void InterfaceProvider::SetConnectionLostClosure(
     const base::Closure& connection_lost_closure) {
   interface_provider_.set_connection_error_handler(connection_lost_closure);