Add Precache.Fetch.ResponseBytes.Daily.

components/precache/core/precache_fetcher.cc

 // Copyright 2013 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.
 
 #include "components/precache/core/precache_fetcher.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <utility>
@@ skipping 702 matching lines @@
       base::Bind(&RetrieveQuotaInfo, precache_database_),
       base::Bind(&PrecacheFetcher::OnQuotaInfoRetrieved, AsWeakPtr()));
 }
 
 void PrecacheFetcher::OnQuotaInfoRetrieved(const PrecacheQuota& quota) {
   quota_ = quota;
   base::Time time_now = base::Time::Now();
   if (IsQuotaTimeExpired(quota_, time_now)) {
     // This is a new day. Update daily quota, that starts today and expires by
     // end of today.
+
+    // If a previous day existed, report its usage.
+    if (quota_.has_start_time()) {
+      UMA_HISTOGRAM_CUSTOM_COUNTS(
+          "Precache.Fetch.ResponseBytes.Daily",
+          unfinished_work_->config_settings().daily_quota_total() -
+              quota_.remaining(),
+          1, kMaxResponseBytes, 100);
+    }
+
     quota_.set_start_time(time_now.LocalMidnight().ToInternalValue());
     quota_.set_remaining(
         unfinished_work_->config_settings().daily_quota_total());
     db_task_runner_->PostTask(
         FROM_HERE,
         base::Bind(&PrecacheDatabase::SaveQuota, precache_database_, quota_));
   }
   StartNextFetch();
 }
 
@@ skipping 149 matching lines @@
       remaining = 0;
     quota_.set_remaining(
         used_bytes > quota_.remaining() ? 0U : quota_.remaining() - used_bytes);
     db_task_runner_->PostTask(
         FROM_HERE,
         base::Bind(&PrecacheDatabase::SaveQuota, precache_database_, quota_));
   }
 }
 
 }  // namespace precache