Find device-dependent disk stats file, and skip disk stats if not available.

metrics_daemon.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_DAEMON_H_
 #define METRICS_DAEMON_H_
 
 #include <dbus/dbus.h>
 #include <glib.h>
 #include <map>
@@ skipping 12 matching lines @@
 }
 
 class MetricsDaemon {
 
  public:
   MetricsDaemon();
   ~MetricsDaemon();
 
   // Initializes.
   void Init(bool testing, MetricsLibraryInterface* metrics_lib,
-            const char* diskstats_path);
+            std::string diskstats_path);
 
   // Does all the work. If |run_as_daemon| is true, daemonizes by
   // forking.
   void Run(bool run_as_daemon);
 
  private:
   friend class MetricsDaemonTest;
   FRIEND_TEST(MetricsDaemonTest, CheckSystemCrash);
   FRIEND_TEST(MetricsDaemonTest, ComputeEpochNoCurrent);
   FRIEND_TEST(MetricsDaemonTest, ComputeEpochNoLast);
@@ skipping 253 matching lines @@
   int usemon_interval_;
 
   // Scheduled daily use monitor source (see ScheduleUseMonitor).
   GSource* usemon_source_;
 
   // Contains the most recent disk stats.
   long int read_sectors_;
   long int write_sectors_;
 
   DiskStatsState diskstats_state_;
-  const char* diskstats_path_;
+  std::string diskstats_path_;
 };
 
 #endif  // METRICS_DAEMON_H_