Factor management of metrics updates into its own class.

chrome/common/page_load_metrics/page_load_metrics_util.h

Index: chrome/common/page_load_metrics/page_load_metrics_util.h
diff --git a/chrome/common/page_load_metrics/page_load_metrics_util.h b/chrome/common/page_load_metrics/page_load_metrics_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..4def3f8727fbb6c43c6aa8f364dc2c9f6ee241ef
--- /dev/null
+++ b/chrome/common/page_load_metrics/page_load_metrics_util.h
@@ -0,0 +1,17 @@
+// 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 CHROME_COMMON_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_UTIL_H_
+#define CHROME_COMMON_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_UTIL_H_
+
+namespace page_load_metrics {
+
+// Amount of time to delay dispatch of metrics. This allows us to batch and send
+// fewer cross-process updates, given that cross-process updates can be
+// expensive.
+const int kBufferTimerDelayMillis = 1000;
+
+}  // namespace page_load_metrics
+
+#endif  // CHROME_COMMON_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_UTIL_H_