Add a type to uniquely identify a Background Fetch

content/browser/background_fetch/background_fetch_registration_id.h

Index: content/browser/background_fetch/background_fetch_registration_id.h
diff --git a/content/browser/background_fetch/background_fetch_registration_id.h b/content/browser/background_fetch/background_fetch_registration_id.h
new file mode 100644
index 0000000000000000000000000000000000000000..b47f8f5f8b1fc07cf8bf551a74d9284fbc2f18a3
--- /dev/null
+++ b/content/browser/background_fetch/background_fetch_registration_id.h
@@ -0,0 +1,51 @@
+// 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_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_REGISTRATION_ID_H_
+#define CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_REGISTRATION_ID_H_
+
+#include <stdint.h>
+#include <string>
+
+#include "base/macros.h"
+#include "content/common/content_export.h"
+#include "url/origin.h"
+
+namespace content {
+
+// The Background Fetch registration id corresponds to the information required
+// to uniquely identify a Background Fetch registration in scope of a profile.
+class CONTENT_EXPORT BackgroundFetchRegistrationId {
+ public:
+  BackgroundFetchRegistrationId(int64_t service_worker_registration_id,
+                                const url::Origin& origin,
+                                const std::string& tag);
+  BackgroundFetchRegistrationId(BackgroundFetchRegistrationId&& other);
+  ~BackgroundFetchRegistrationId();
+
+  // Returns whether the |other| registration id are identical or different.
+  bool operator==(const BackgroundFetchRegistrationId& other) const;
+  bool operator!=(const BackgroundFetchRegistrationId& other) const;
+
+  // Enables this type to be used in an std::map and std::set.
+  // TODO(peter): Delete this when we switch away from using maps.
+  bool operator<(const BackgroundFetchRegistrationId& other) const;
+
+  int64_t service_worker_registration_id() const {
+    return service_worker_registration_id_;
+  }
+  const url::Origin& origin() const { return origin_; }
+  const std::string& tag() const { return tag_; }
+
+ private:
+  int64_t service_worker_registration_id_;
+  url::Origin origin_;

[harkness, 2017/03/26 14:47:23]

Do we need the origin to uniquely identify this? I thought the
service_worker_registration_id and tag would be enough. 

[Peter Beverloo, 2017/03/26 21:51:08]

Yes, but (a) dispatching events to a Service Worker is more efficient if we know
the origin, and (b) this gives us another layer of protection in case of data
being out of sync when one or more databases corrupt. (E.g. the Service Worker
Database.)

+  std::string tag_;
+
+  DISALLOW_COPY_AND_ASSIGN(BackgroundFetchRegistrationId);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_REGISTRATION_ID_H_