Move function to compute the max number of threads in a TaskScheduler pool to base/.

base/task_scheduler/initialization_util.cc

+// Copyright 2016 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 "base/task_scheduler/initialization_util.h"
+
+#include <algorithm>
+
+#include "base/sys_info.h"
+
+namespace base {
+
+int RecommendedMaxNumberOfThreadsInPool(int min,
+                                        int max,
+                                        double cores_multiplier,
+                                        int offset) {
+  const int num_of_cores = SysInfo::NumberOfProcessors();
+  const int threads = std::ceil<int>(num_of_cores * cores_multiplier) + offset;
+  return std::min(max, std::max(min, threads));
+}
+
+}  // namespace base