Initial framework setup and skeleton for BackgroundFetchContext

content/browser/background_fetch/fetch_request.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_BROWSER_BACKGROUND_FETCH_FETCH_REQUEST_H_
+#define CONTENT_BROWSER_BACKGROUND_FETCH_FETCH_REQUEST_H_
+

[Peter Beverloo, 2017/02/13 18:35:06]

nit: <string>

[harkness, 2017/02/14 13:52:47]

Done.

+#include "content/common/content_export.h"
+#include "url/origin.h"
+
+namespace content {
+
+class DownloadItem;
+
+// Simple class to encapsulate the components of a fetch request.
+class CONTENT_EXPORT FetchRequest {

[Peter Beverloo, 2017/02/13 18:35:06]

We're really going to have to think about this class. Logically we'll have a
background fetch "registration" that has metadata, which has one or more
background fetch requests, each of which has a ServiceWorkerFetchRequest object,
as well as data associating it with the in-progress download (GUID and
download_item). Part of that has to persist on disk, part of that doesn't.

[harkness, 2017/02/14 13:52:47]

Yes, how that registration is divided between the (to-be-written)BatchManager
and the DataManager is an open question as well.

+ public:
+  FetchRequest();
+  FetchRequest(const url::Origin& origin,
+               const url::Origin& url,

[Peter Beverloo, 2017/02/13 18:35:06]

Why is |url| a url::Origin? At the very least it needs to be a GURL.

[harkness, 2017/02/14 13:52:47]

Good point.

+               const std::string& tag,
+               DownloadItem* download_item);
+  FetchRequest(const FetchRequest& request);

[Peter Beverloo, 2017/02/13 18:35:06]

q: where would we copy instances of this object?

[harkness, 2017/02/14 13:52:47]

map uses it

[Peter Beverloo, 2017/02/14 15:05:52]

Let's add a TODO to get rid of it since the map is temporary. It'll end up
making copies of the std::strings too, including the url::Origin backings, so
that's eight allocations *per copy*.

+  ~FetchRequest();
+
+  const std::string& guid() const { return guid_; }
+  const url::Origin& origin() const { return origin_; }
+  const url::Origin& url() const { return url_; }
+  const std::string& tag() const { return tag_; }
+  const DownloadItem* download_item() const { return download_item_; }
+
+ private:
+  std::string guid_;
+  url::Origin origin_;
+  url::Origin url_;
+  std::string tag_;
+  DownloadItem* download_item_;

[Peter Beverloo, 2017/02/13 18:35:06]

nit: document what the ownership model is

[harkness, 2017/02/14 13:52:46]

I removed this, since I don't need DownloadItems until I have the download
observers.

+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_BACKGROUND_FETCH_FETCH_REQUEST_H_