[PresentationAPI] Implementing start/joinSession from WebPresentationClient to PresentationService.

content/renderer/presentation/presentation_session_client.h

+// Copyright 2015 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_SESSION_CLIENT_H_
+#define CONTENT_RENDERER_PRESENTATION_PRESENTATION_SESSION_CLIENT_H_
+
+#include "base/compiler_specific.h"
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/platform/modules/presentation/WebPresentationSessionClient.h"
+
+namespace content {
+
+class PresentationSessionDispatcher;
+
+// PresentationSessionClient is passed to the Blink layer if presentation
+// session has been created successfully. Owned by the callback.
+class CONTENT_EXPORT PresentationSessionClient
+    : public NON_EXPORTED_BASE(blink::WebPresentationSessionClient) {
+ public:
+  explicit PresentationSessionClient(PresentationSessionDispatcher* dispatcher);
+  ~PresentationSessionClient() override;
+
+  // WebPresentationSessionClient implementation.
+  virtual blink::WebString getUrl();
+  virtual blink::WebString getId();
+
+ private:
+  blink::WebString url_;
+  blink::WebString id_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PRESENTATION_PRESENTATION_SESSION_CLIENT_H_