[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..996ccd9cd22505c19a0372763133b8f9621091f2
--- /dev/null
+++ b/content/browser/background_sync/background_sync_metrics.h
@@ -0,0 +1,49 @@
+// 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"
+
+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 RegistrationResult {
+    REGISTRATION_RESULT_SUCCEEDED,
+    REGISTRATION_RESULT_FAILED,
+    REGISTRATION_RESULT_DUPLICATE,
+    NUM_REGISTRATION_RESULT_TYPES
+  };

[jkarlin, 2015/07/13 16:51:13]

Why not use BackgroundSyncManager::ErrorType?

[iclelland, 2015/07/13 19:34:31]

We need to mirror the enum in histograms.xml, which records duplicate successes
distinctly from new-registration successes. (I want to track the number of times
that an identical sync is registered.)

Also, I was hoping to not have to depend on background_sync_manager.h here
(trying to avoid circular dependencies) but if that really is the best enum to
use -- and there's no better place to move ErrorType -- then I'll do that.

Maybe the better thing for recording duplicates is to tack on a boolean param to
CountRegistration for is_duplicate_registration, and leave the enums to the
implementation. I'll switch that.

[jkarlin, 2015/07/14 15:54:10]

Thanks for explaining, I hadn't noticed the "duplicate" distinction before and
mistakenly thought ErrorType was the same as the new enum. ErrorType can be
moved into its own file, that's no problem. If you prefer the original approach
you took, with the separate enum, that also works for me.

+
+  // 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.
+  static void RecordSyncEventHandlingTime(const base::TimeDelta& time);
+
+  // Records the result of trying to register a sync. |could_fire| indicates
+  // whether the network/power was sufficient for the sync to fire immediately
+  // at the time it was registered.
+  static void CountRegistration(SyncPeriodicity periodicity,
+                                bool could_fire,
+                                RegistrationResult result);
+
+  // Records the result of trying to unregister a sync.
+  static void CountUnregistration(SyncPeriodicity periodicity, bool success);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(BackgroundSyncMetrics);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_METRICS_H_