[Presentation API] Additional plumbing for PresentationServiceImpl.

content/public/browser/presentation_session.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_PUBLIC_BROWSER_PRESENTATION_SESSION_H_
+#define CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_H_
+
+#include <string>
+
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Represents a presentation session that has been established via either
+// browser actions or Presentation API.
+struct CONTENT_EXPORT PresentationSessionInfo {
+  PresentationSessionInfo(const std::string& presentation_url,
+                          const std::string& presentation_id);
+  ~PresentationSessionInfo();
+
+  const std::string presentation_url;
+  const std::string presentation_id;
+};
+
+// Possible reasons why an attempt to create a presentation session failed.
+enum CONTENT_EXPORT PresentationErrorType {
+  PRESENTATION_ERROR_NO_AVAILABLE_SCREENS,
+  PRESENTATION_ERROR_SESSION_REQUEST_CANCELLED,
+  PRESENTATION_ERROR_NO_PRESENTATION_FOUND,
+  PRESENTATION_ERROR_UNKNOWN,
+};
+
+// Struct returned when an attempt to create a presentation session failed.
+struct CONTENT_EXPORT PresentationError {
+  PresentationError(PresentationErrorType error_type,
+                    const std::string& message);
+  ~PresentationError();
+
+  const PresentationErrorType error_type;
+  const std::string message;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_H_