Add initial Controller to DownloadService

components/download/internal/entry_utils.cc

+// 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.
+
+#include "components/download/internal/entry_utils.h"
+
+#include "components/download/internal/entry.h"
+
+namespace download {
+namespace util {
+
+uint32_t GetNumberOfEntriesForClient(DownloadClient client,
+                                     const std::vector<Entry*>& entries) {
+  uint32_t count = 0;
+  for (auto* entry : entries)
+    if (entry->client == client)
+      count++;
+
+  return count;
+}
+
+std::map<DownloadClient, std::vector<std::string>> MapReduceEntriesToClients(
+    const std::set<DownloadClient>& clients,
+    const std::vector<Entry*>& entries) {
+  std::map<DownloadClient, std::vector<std::string>> categorized;
+
+  for (auto* entry : entries) {
+    DownloadClient client = entry->client;
+    if (clients.find(client) == clients.end())
+      client = DownloadClient::INVALID;
+
+    categorized[client].push_back(entry->guid);
+  }
+
+  return categorized;

[xingliu, 2017/05/27 00:25:32]

optional nit: this is a cool name, but the caller need to reduce themselves.

[David Trainor- moved to gerrit, 2017/05/30 18:55:23]

Done.

+}
+
+}  // namespace util
+}  // namespace download