Add a Model to the download component.

components/download/internal/entry.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 COMPONENTS_DOWNLOAD_INTERNAL_ENTRY_H_
+#define COMPONENTS_DOWNLOAD_INTERNAL_ENTRY_H_
+
+#include "components/download/public/client.h"
+#include "components/download/public/clients.h"
+#include "components/download/public/download_params.h"
+
+namespace download {
+
+// An entry in the Model that represents a scheduled download.
+struct Entry {
+ public:
+  enum class State {
+    // A newly added download.  The Entry is not guaranteed to be persisted in
+    // the model yet.
+    NEW = 0,
+
+    // The download has been persisted and is available to start, pending
+    // scheduler criteria.
+    AVAILABLE = 1,
+
+    // The download is active.  The DownloadDriver is aware of it and it is
+    // either being downloaded or suspended by the scheduler due to device
+    // characteristics or throttling.
+    ACTIVE = 2,
+
+    // The download has been paused by the owning Client.  The download will not
+    // be run until it is resumed by the Client.
+    PAUSED = 3,
+
+    // The download is 'complete' by some definition of that term (could have
+    // failed, could have succeeded, etc.).  It is ready to have UMA logs saved.
+    COMPLETE = 4,
+
+    // The download is finished.  We are leaving this entry around to make sure
+    // the files on disk are cleaned up.
+    WATCHDOG = 5,
+  };
+
+  Entry();
+  Entry(const Entry& other);
+  ~Entry();
+
+  // The feature that is requesting this download.
+  DownloadClient client = DownloadClient::INVALID;
+
+  // A unique GUID that represents this download.  See | base::GenerateGUID()|.
+  std::string guid;
+
+  // The parameters that determine under what device conditions this download
+  // will occur.
+  SchedulingParams scheduling_params;
+
+  // The parameters that define the actual download request to make.
+  RequestParams request_params;
+
+  // The state of the download to help the scheduler and loggers make the right
+  // decisions about the download object.
+  State state = State::NEW;
+};
+
+}  // namespace download
+
+#endif  // COMPONENTS_DOWNLOAD_INTERNAL_ENTRY_H_