Move Navigation.MainFrameScheme UMA recording to //components.

components/navigation_metrics/navigation_metrics.h

Index: components/navigation_metrics/navigation_metrics.h
diff --git a/components/navigation_metrics/navigation_metrics.h b/components/navigation_metrics/navigation_metrics.h
new file mode 100644
index 0000000000000000000000000000000000000000..fce4ffd53ba5ee8d6ec123a1e05bf98b12e134b9
--- /dev/null
+++ b/components/navigation_metrics/navigation_metrics.h
@@ -0,0 +1,16 @@
+// Copyright (c) 2013 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_NAVIGATION_METRICS_NAVIGATION_METRICS_H_
+#define COMPONENTS_NAVIGATION_METRICS_NAVIGATION_METRICS_H_
+
+class GURL;
+
+namespace navigation_metrics {
+
+void RecordMainFrameNavigation(const GURL& url);
+
+}  // namespace navigation_metrics
+
+#endif  // COMPONENTS_NAVIGATION_METRICS_NAVIGATION_METRICS_H_