Add a histogram to measure browser window display

chrome/common/startup_metric_utils.cc

Index: chrome/common/startup_metric_utils.cc
diff --git a/chrome/common/startup_metric_utils.cc b/chrome/common/startup_metric_utils.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bb2057acdb15c29f1f21eaaa79d0586d03acee3f
--- /dev/null
+++ b/chrome/common/startup_metric_utils.cc
@@ -0,0 +1,25 @@
+// Copyright (c) 2012 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 "chrome/common/startup_metric_utils.h"
+
+namespace {
+
+// Mark as volatile to defensively make sure usage is thread-safe.
+// Note that at the time of this writing, access is only on the UI thread.
+static volatile bool g_non_browser_ui_displayed = false;
+
+}  // namespace
+
+namespace startup_metric_utils {
+
+bool WasNonBrowserUIDisplayed() {
+  return g_non_browser_ui_displayed;
+}
+
+void SetNonBrowserUIDisplayed() {
+  g_non_browser_ui_displayed = true;
+}
+
+}  // namespace startup_metric_utils