[CacheStorage] Add metrics to the scheduler

content/browser/cache_storage/cache_storage_histogram_macros.h

+// Copyright 2016 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_CACHE_STORAGE_CACHE_STORAGE_HISTOGRAM_MACROS_H_
+#define CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_HISTOGRAM_MACROS_H_
+
+#include "base/metrics/histogram_macros.h"
+#include "content/browser/cache_storage/cache_storage_scheduler_client.h"
+
+namespace content {
+
+// Metrics to make it easier to write histograms for several clients.
+#define CACHE_STORAGE_SCHEDULER_UMA_THUNK(uma_type, args) \
+  UMA_HISTOGRAM_##uma_type args
+#define CACHE_STORAGE_SCHEDULER_UMA(uma_type, uma_name, client_type, ...)     \
+  do {                                                                        \
+    switch (client_type) {                                                    \
+      case CacheStorageSchedulerClient::CLIENT_STORAGE:                       \
+        CACHE_STORAGE_SCHEDULER_UMA_THUNK(                                    \
+            uma_type, ("ServiceWorkerCache.CacheStorage.Scheduler." uma_name, \
+                       ##__VA_ARGS__));                                       \
+        break;                                                                \
+      case CacheStorageSchedulerClient::CLIENT_CACHE:                         \
+        CACHE_STORAGE_SCHEDULER_UMA_THUNK(                                    \
+            uma_type,                                                         \
+            ("ServiceWorkerCache.Cache.Scheduler." uma_name, ##__VA_ARGS__)); \
+        break;                                                                \
+      case CacheStorageSchedulerClient::CLIENT_BACKGROUND_SYNC:               \
+        CACHE_STORAGE_SCHEDULER_UMA_THUNK(                                    \
+            uma_type,                                                         \
+            ("ServiceWorkerCache.BackgroundSyncManager.Scheduler." uma_name,  \
+             ##__VA_ARGS__));                                                 \
+        break;                                                                \
+      default:                                                                \
+        NOTREACHED();                                                         \
+        break;                                                                \
+    }                                                                         \
+  } while (0)
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_HISTOGRAM_MACROS_H_