Separate Remote InterfaceProvider again, and add a new client lib type for it.

services/shell/public/cpp/remote_interface_registry.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SERVICES_SHELL_PUBLIC_CPP_REMOTE_INTERFACE_REGISTRY_H_
+#define SERVICES_SHELL_PUBLIC_CPP_REMOTE_INTERFACE_REGISTRY_H_
+
+#include "services/shell/public/interfaces/interface_provider.mojom.h"
+
+namespace shell {
+
+class RemoteInterfaceRegistry {

[Ken Rockot(use gerrit already), 2016/06/16 23:48:58]

nit: Documentation. It's worth calling out that this is an InterfaceProviderPtr
with the ability to override outgoing connections for testing.

+ public:
+  class TestApi {
+   public:
+    explicit TestApi(RemoteInterfaceRegistry* registry) : registry_(registry) {}
+    ~TestApi() {}
+
+    template <typename Interface>
+    void SetBinderForName(
+        const std::string& name,
+        const base::Callback<void(mojo::InterfaceRequest<Interface>)>& binder) {
+      registry_->SetBinderForName(name, binder);
+    }
+
+    void ClearBinders() {
+      registry_->ClearBinders();
+    }
+
+   private:
+    RemoteInterfaceRegistry* registry_;
+    DISALLOW_COPY_AND_ASSIGN(TestApi);
+  };
+
+  explicit RemoteInterfaceRegistry(
+      mojom::InterfaceProviderPtr remote_interfaces);
+  ~RemoteInterfaceRegistry();
+
+  // Returns a raw pointer to the remote InterfaceProvider.
+  mojom::InterfaceProvider* GetInterfaceProvider();
+
+  // Sets a closure to be run when the remote InterfaceProvider pipe is closed.
+  void SetConnectionLostClosure(const base::Closure& connection_lost_closure);
+
+  // Binds |ptr| to an implementation of Interface in the remote application.
+  // |ptr| can immediately be used to start sending requests to the remote
+  // interface.
+  template <typename Interface>
+  void GetInterface(mojo::InterfacePtr<Interface>* ptr) {
+    mojo::MessagePipe pipe;
+    ptr->Bind(mojo::InterfacePtrInfo<Interface>(std::move(pipe.handle0), 0u));
+
+    // Local binders can be registered via TestApi.
+    auto it = binders_.find(Interface::Name_);
+    if (it != binders_.end()) {
+      it->second.Run(std::move(pipe.handle1));
+      return;
+    }
+    remote_interfaces_->GetInterface(Interface::Name_, std::move(pipe.handle1));
+  }
+  template <typename Interface>
+  void GetInterface(mojo::InterfaceRequest<Interface> request) {
+    GetInterface(Interface::Name_, std::move(request.PassMessagePipe()));
+  }
+  void GetInterface(const std::string& name,
+                    mojo::ScopedMessagePipeHandle request_handle);
+
+ private:
+  template <typename Interface>
+  void SetBinderForName(
+      const std::string& name,
+      const base::Callback<void(mojo::InterfaceRequest<Interface>)>& binder) {
+    binders_[name] = binder;
+  }
+  void ClearBinders();
+
+  using BinderMap = std::map<
+      std::string, base::Callback<void(mojo::ScopedMessagePipeHandle)>>;
+  BinderMap binders_;
+
+  mojom::InterfaceProviderPtr remote_interfaces_;
+
+  DISALLOW_COPY_AND_ASSIGN(RemoteInterfaceRegistry);
+};
+
+}  // namespace shell
+
+#endif  // SERVICES_SHELL_PUBLIC_CPP_REMOTE_INTERFACE_REGISTRY_H_