Enable connection to Mojo services from Blink

third_party/WebKit/Source/platform/ServiceConnector.h

+// Copyright 2015 The Chromium Authors. All rights reserved.

[Ken Rockot(use gerrit already), 2016/12/05 20:54:18]

nit: 2016

[blundell, 2016/12/15 17:04:52]

Done. Hopefully this lands before it needs to be changed again :).

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ServiceConnector_h
+#define ServiceConnector_h
+
+#include "mojo/public/cpp/bindings/binding.h"
+#include "public/platform/Platform.h"
+#include "services/service_manager/public/interfaces/connector.mojom-blink.h"
+#include "wtf/StdLibExtras.h"
+
+namespace blink {
+
+// ServiceConnector supports connecting to Mojo services by name.
+class ServiceConnector {
+ public:
+  static ServiceConnector& instance() {
+    DEFINE_STATIC_LOCAL(ServiceConnector, instance, ());
+    return instance;
+  }
+
+  template <typename Interface>
+  void ConnectToInterface(const char* serviceName,

[esprehn, 2016/12/02 02:23:14]

These should all be lowerCase() for now.

[blundell, 2016/12/15 17:04:52]

Done.

+                          mojo::InterfaceRequest<Interface> interfacePtr) {

[Noel Gordon, 2016/12/07 07:09:26]

|interfacePtr| ??  Isn't the argument a request?  Maybe we should call it a
request?

[blundell, 2016/12/15 17:04:52]

Great catch, thanks. Done.

+    InitializeIfNecessary();
+
+    if (!m_connector.is_bound())
+      return;
+
+    service_manager::mojom::blink::IdentityPtr remoteIdentity(
+        service_manager::mojom::blink::Identity::New());
+    remoteIdentity->name = serviceName;
+    remoteIdentity->user_id = service_manager::mojom::blink::kInheritUserID;
+    remoteIdentity->instance = "";
+
+    service_manager::mojom::blink::InterfaceProviderPtr remoteInterfaces;
+    m_connector->Connect(std::move(remoteIdentity), GetProxy(&remoteInterfaces),
+                         nullptr,
+                         base::Bind(&ServiceConnector::OnConnectionCompleted));
+
+    remoteInterfaces->GetInterface(Interface::Name_,
+                                   interfacePtr.PassMessagePipe());
+  }
+
+ private:
+  ServiceConnector() : m_initialized(false) {}

[Noel Gordon, 2016/12/07 07:09:26]

Is this needed? Could we init the class fully at construction-time?

[blundell, 2016/12/15 17:04:51]

The recommended practice in Mojo is to set up all connections on-demand. That
said, with rockot@'s suggested refactoring this becomes simpler and the need for
a distinct InitializeIfNecessary() method goes away.

+
+  void InitializeIfNecessary() {

[esprehn, 2016/12/02 02:23:14]

initializeIfNeeded()

[blundell, 2016/12/15 17:04:52]

Done.

+    if (m_initialized)
+      return;
+
+    m_connector = Platform::current()->serviceConnector();
+    m_initialized = true;
+  }
+
+  static void OnConnectionCompleted(
+      service_manager::mojom::ConnectResult result,
+      const WTF::String& targetUserID) {}
+
+  bool m_initialized;
+  service_manager::mojom::blink::ConnectorPtr m_connector;
+};
+
+}  // namespace blink
+
+#endif  // ServiceConnector_h