Split UserMetrics into API vs. implementation. Move API to content/public.

content/public/browser/user_metrics.h

Index: content/public/browser/user_metrics.h
diff --git a/content/browser/user_metrics.h b/content/public/browser/user_metrics.h
similarity index 86%
copy from content/browser/user_metrics.h
copy to content/public/browser/user_metrics.h
index ae04af3d49aa6220c2dee4f09835f2e72d3ce7b3..8e9e4d45eb580663f1e5c60515717a84a75d74de 100644
--- a/content/browser/user_metrics.h
+++ b/content/public/browser/user_metrics.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CONTENT_BROWSER_USER_METRICS_H_
-#define CONTENT_BROWSER_USER_METRICS_H_
+#ifndef CONTENT_PUBLIC_BROWSER_USER_METRICS_H_
+#define CONTENT_PUBLIC_BROWSER_USER_METRICS_H_
 #pragma once
 
 #include <string>
@@ -12,6 +12,10 @@
 
 // This module provides some helper functions for logging actions tracked by
 // the user metrics system.
+//
+// Note that we do not wrap this in the content namespace to avoid
+// making it more difficult to comply with the single-line requirement
+// discussed for UserMetrics::RecordAction below.
 
 
 // UserMetricsAction exist purely to standardize on the paramters passed to
@@ -50,10 +54,6 @@ class CONTENT_EXPORT UserMetrics {
   // you need to also update the rules for extracting known actions in
   // chrome/tools/extract_actions.py.
   static void RecordComputedAction(const std::string& action);
-
- private:
-  static void Record(const char *action);
-  static void CallRecordOnUI(const std::string& action);
 };
 
-#endif  // CONTENT_BROWSER_USER_METRICS_H_
+#endif  // CONTENT_PUBLIC_BROWSER_USER_METRICS_H_