[Background Sync] Gather UMA data for Background Sync

content/browser/background_sync/background_sync_metrics.h

Index: content/browser/background_sync/background_sync_metrics.h
diff --git a/content/browser/background_sync/background_sync_metrics.h b/content/browser/background_sync/background_sync_metrics.h
new file mode 100644
index 0000000000000000000000000000000000000000..01ece3f146990fd7fb9db83f5cc2f5154f046c8d
--- /dev/null
+++ b/content/browser/background_sync/background_sync_metrics.h
@@ -0,0 +1,56 @@
+// Copyright 2015 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 CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_METRICS_H_
+#define CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_METRICS_H_
+
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "content/browser/background_sync/background_sync.pb.h"
+#include "content/browser/background_sync/background_sync_manager.h"
+
+namespace content {
+
+// This class contains the logic for recording usage metrics for the Background
+// Sync API. It is stateless, containing only static methods, so it can be used
+// by any of the Background Sync code, without needing to be instantiated
+// explicitly.
+class BackgroundSyncMetrics {
+ public:
+  enum RegistrationCouldFire {
+    REGISTRATION_COULD_NOT_FIRE,
+    REGISTRATION_COULD_FIRE
+  };
+
+  enum RegistrationIsDuplicate {
+    REGISTRATION_IS_NOT_DUPLICATE,
+    REGISTRATION_IS_DUPLICATE
+  };
+
+  // Records the result of a single sync event firing.
+  static void RecordEventResult(SyncPeriodicity periodicity, bool result);
+
+  // Records the total time spent running all sync events.

[jkarlin, 2015/07/15 17:17:06]

This makes it sound like it's counting up all sync event time forever. Perhaps,
"records the time spent running a batch of sync events".

[iclelland, 2015/07/15 18:01:35]

Done.

+  static void RecordSyncEventHandlingTime(const base::TimeDelta& time);

[jkarlin, 2015/07/15 17:17:06]

Perhaps RecordBatchSyncEventHandlingTime to make it clear that it's not
recording a single sync event.

[iclelland, 2015/07/15 18:01:35]

Done.

+
+  // Records the result of trying to register a sync. |could_fire| indicates
+  // whether the network/power was sufficient for the sync to fire immediately

[jkarlin, 2015/07/15 17:17:06]

network/power is specific and the conditions might change over time. Suggest,
"indicates whether the conditions were sufficient for..."

[iclelland, 2015/07/15 18:01:35]

Done.

+  // at the time it was registered.
+  static void CountRegistration(
+      SyncPeriodicity periodicity,
+      RegistrationCouldFire could_fire,
+      RegistrationIsDuplicate registration_is_duplicate,
+      BackgroundSyncManager::ErrorType result);
+
+  // Records the result of trying to unregister a sync.
+  static void CountUnregistration(SyncPeriodicity periodicity,
+                                  BackgroundSyncManager::ErrorType result);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(BackgroundSyncMetrics);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_METRICS_H_