[Presentation API] (4th)(1-UA blink side) Add WebPresentationConnection and WebPresentationConnecti…

content/renderer/presentation/presentation_connection_proxy.h

+// Copyright 2017 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 CONTENT_RENDERER_PRESENTATION_PRESENTATION_CONNECTION_PROXY_H_
+#define CONTENT_RENDERER_PRESENTATION_PRESENTATION_CONNECTION_PROXY_H_
+
+#include "base/callback.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "third_party/WebKit/public/platform/modules/presentation/WebPresentationConnectionProxy.h"
+#include "third_party/WebKit/public/platform/modules/presentation/presentation.mojom.h"
+
+namespace blink {
+class WebPresentationConnection;
+}  // namespace blink
+
+namespace content {
+
+using OnMessageCallback = base::Callback<void(bool)>;

[mlamouri (slow - plz ping), 2017/01/26 22:18:02]

Can you move this inside the class? Otherwise, you are defining
content::OnMessageCallback for everyone who includes this header.

[zhaobin, 2017/01/26 22:48:14]

Done.

+
+// This class connects PresentationConnection owned by one frame with
+// PresentationConnection owned by a different frame.
+//
+// PresentationConnectionProxy's ctor sets |source_connection_| to
+// PresentationConnection object owned by one frame.
+//
+// To connect |controller_connection_proxy| on controlling frame with
+// |receiver_connection_proxy| on receiver frame:
+// 1. On controlling frame, create PresentationConnection object and
+//    ControllerConnectionProxy object |controller_connection_proxy|;
+// 2. Create |target_connection_request|, an interface request of
+//    controller proxy's |target_connection_| by invoking:
+//       ControllerConnectionProxy::MakeRemoteRequest() {
+//           return mojo::MakeRequest(&target_connection_);
+//       }
+// 3. Pass |controller_connection_proxy|'s interface pointer and
+//    |target_connection_request| to browser;
+// 4. Browser passes |controller_connection_proxy|'s interface pointer and
+//    |target_connection_request| to receiver frame;
+// 5. On receiver frame, create PresentationConnection object and
+//    ReceiverConnectionProxy object |receiver_connection_proxy|;
+// 6. Bind |target_connection_request| with |receiver_connection_proxy| by
+//    invoking:
+//        ReceiverConnectionProxy::Bind(target_connection_request);
+// 7. Set receiver proxy's |target_connection_| to
+//    |controller_connection_proxy|'s interface pointer:
+//        ReceiverConnectionProxy::BindTargetConnection(
+//            blink::mojom::PresentationConnectionPtr connection) {
+//          target_connection_ = std::move(connection);
+//          ...
+//        }
+//
+// When both |source_connection_| and |target_connection_| are set,
+// we can send message or notify state changes between controller and receiver.
+//
+// To send message from controlling frame to receiver frame:
+// 1. Controlling frame invokes connection.sendMessage();
+// 2. This call is delegated to controller presentation connection proxy's
+//    SendConnectionMessage().
+//      ControllerConnectionProxy::SendConnectionMessage() {
+//         target_connection_->OnMessage();
+//      }
+// 3. ReceiverConnectionProxy::OnMessage() is invoked.
+// 4. connection.onmessage event on receiver frame is fired.
+//
+// Sending message from receiver frame to controlling frame and notifying state
+// changes works the same.
+//
+// Instance of this class is created for both offscreen and non offscreen
+// presentations.

[mlamouri (slow - plz ping), 2017/01/26 22:18:02]

That documentation looks great! :)

+class CONTENT_EXPORT PresentationConnectionProxy
+    : public NON_EXPORTED_BASE(blink::WebPresentationConnectionProxy),
+      public NON_EXPORTED_BASE(blink::mojom::PresentationConnection) {
+ public:
+  ~PresentationConnectionProxy() override;
+
+  virtual void SendConnectionMessage(
+      blink::mojom::ConnectionMessagePtr connection_message,
+      const OnMessageCallback& callback) const;
+
+  // blink::mojom::PresentationConnection implementation
+  void OnMessage(blink::mojom::ConnectionMessagePtr message,
+                 const OnMessageCallback& callback) override;
+  void DidChangeState(blink::mojom::PresentationConnectionState state) override;
+
+ protected:
+  explicit PresentationConnectionProxy(
+      blink::WebPresentationConnection* source_connection);
+  mojo::Binding<blink::mojom::PresentationConnection> binding_;
+  mojo::InterfacePtr<blink::mojom::PresentationConnection>
+      target_connection_ptr_;
+
+ private:
+  // Raw pointer to Blink connection object owning this proxy object. Does not
+  // take ownership.
+  blink::WebPresentationConnection* const source_connection_;
+};
+
+// Represents PresentationConnectionProxy object on controlling frame.
+class CONTENT_EXPORT ControllerConnectionProxy
+    : public PresentationConnectionProxy {
+ public:
+  explicit ControllerConnectionProxy(
+      blink::WebPresentationConnection* controller_connection);
+  ~ControllerConnectionProxy() override;
+
+  blink::mojom::PresentationConnectionPtr Bind();
+  blink::mojom::PresentationConnectionRequest MakeRemoteRequest();
+};
+
+// Represents PresentationConnectionProxy object on receiver frame.
+class CONTENT_EXPORT ReceiverConnectionProxy
+    : public PresentationConnectionProxy {
+ public:
+  explicit ReceiverConnectionProxy(
+      blink::WebPresentationConnection* receiver_connection);
+  ~ReceiverConnectionProxy() override;
+
+  void Bind(
+      blink::mojom::PresentationConnectionRequest receiver_connection_request);
+
+  // Sets |target_connection_ptr_| to |controller_connection_ptr|. Should be
+  // called only once.
+  void BindControllerConnection(
+      blink::mojom::PresentationConnectionPtr controller_connection_ptr);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PRESENTATION_PRESENTATION_CONNECTION_PROXY_H_