Add support for user actions to the metrics library and the metrics clients.

metrics_library.h

 // Copyright (c) 2010 The Chromium OS 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 METRICS_LIBRARY_H_
 #define METRICS_LIBRARY_H_
 
 #include <sys/types.h>
 #include <string>
 
@@ skipping 51 matching lines @@
   // 0 is the implicit underflow bucket.
   // [|max|,infinity) is the implicit overflow bucket.
   //
   // An enumaration histogram requires |max| + 1 number of
   // buckets. Note that the memory allocated in Chrome for each
   // histogram is proportional to the number of buckets. Therefore, it
   // is strongly recommended to keep this number low (e.g., 50 is
   // normal, while 100 is high).
   bool SendEnumToUMA(const std::string& name, int sample, int max);
 
+  // Sends a user action to Chrome for transport to UMA and returns true on
+  // success. This method results in the equivalent of an asynchronous
+  // non-blocking RPC to UserMetrics::RecordAction (see the comments in
+  // chrome/browser/chromeos/external_metrics.cc and
+  // chrome/browser/metrics/user_metrics.h on how to register new user actions).
+  //
+  // |action| is the user-generated event (e.g., "MuteKeyPressed").
+  bool SendUserActionToUMA(const std::string& action);
+
   // Sends to Autotest and returns true on success.
   static bool SendToAutotest(const std::string& name, int value);
 
  private:
   friend class CMetricsLibraryTest;
   friend class MetricsLibraryTest;
   FRIEND_TEST(MetricsLibraryTest, AreMetricsEnabled);
   FRIEND_TEST(MetricsLibraryTest, FormatChromeMessage);
   FRIEND_TEST(MetricsLibraryTest, FormatChromeMessageTooLong);
   FRIEND_TEST(MetricsLibraryTest, IsDeviceMounted);
@@ skipping 27 matching lines @@
   static time_t cached_enabled_time_;
 
   // Cached state of whether or not metrics were enabled.
   static bool cached_enabled_;
 
   const char* uma_events_file_;
   const char* consent_file_;
 };
 
 #endif  // METRICS_LIBRARY_H_