ash:Shelf - Added UMA stats for ShelfAlignment

chrome/browser/metrics/metrics_service.cc

 // 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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is typically created at application startup.  It is
@@ skipping 134 matching lines @@
 // saved for re-transmission.  These duplicates could be filtered out server
 // side, but are not expected to be a significant problem.
 //
 //
 //------------------------------------------------------------------------------
 
 #include "chrome/browser/metrics/metrics_service.h"
 
 #include <algorithm>
 
+#include "ash/launcher/launcher.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/guid.h"
 #include "base/md5.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
@@ skipping 981 matching lines @@
 
 void MetricsService::SaveLocalState() {
   PrefService* pref = g_browser_process->local_state();
   if (!pref) {
     NOTREACHED();
     return;
   }
 
   RecordCurrentState(pref);
 
+#if defined(OS_CHROMEOS)
+  // Query the current state of the shelf alignment to gather an impression of
+  // how much user time is being spent in each alignment.
+  ash::Launcher::ForPrimaryDisplay()->RecordCurrentAlignmentForUMAHistogram(

[James Cook, 2013/10/30 16:49:12]

Now that I think about it more, this really needs to be on a repeating task in
Ash.  The metrics service shouldn't be responsible for querying all the modules
that need periodic information to record.  Sorry to give you bad advice before.

See chrome/browser/chromeos/memory/oom_priority_manager.cc
RecordRecentTabDiscard() for how to use a repeating timer for this.

I would introduce some kind of "RecordPeriodicStatistics" function or class in
Ash and stick the code there.  It should have a timer that is explicitly started
and stopped when ash::Shell is initialized and torn down.

+      "Ash.ShelfAlignmentOverTime");
+#endif
+
   // TODO(jar):110021 Does this run down the batteries????
   ScheduleNextStateSave();
 }
 
 
 //------------------------------------------------------------------------------
 // Recording control methods
 
 void MetricsService::OpenNewLog() {
   DCHECK(!log_manager_.current_log());
@@ skipping 702 matching lines @@
   if (local_state) {
     const PrefService::Preference* uma_pref =
         local_state->FindPreference(prefs::kMetricsReportingEnabled);
     if (uma_pref) {
       bool success = uma_pref->GetValue()->GetAsBoolean(&result);
       DCHECK(success);
     }
   }
   return result;
 }