precache: Fix top_resources_count + experiments.

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 725 matching lines @@
 void PrecacheFetcher::OnManifestFetchComplete(int64_t host_visits,
                                               const Fetcher& source) {
   DCHECK(unfinished_work_->has_config_settings());
   UpdateStats(source.response_bytes(), source.network_response_bytes());
   if (source.network_url_fetcher() == nullptr) {
     pool_.DeleteAll();  // Cancel any other ongoing request.
   } else {
     PrecacheManifest manifest;
 
     if (ParseProtoFromFetchResponse(*source.network_url_fetcher(), &manifest)) {
-      const int32_t len =
-          std::min(manifest.resource_size(),
-                   unfinished_work_->config_settings().top_resources_count());
       const uint64_t resource_bitset =
           GetResourceBitset(manifest, experiment_id_);
-      for (int i = 0; i < len; ++i) {
+      const int32_t max_to_include =
+          unfinished_work_->config_settings().top_resources_count();
+      int32_t num_included = 0;
+      for (int i = 0;
+           i < manifest.resource_size() && num_included < max_to_include; ++i) {
         if (((0x1ULL << i) & resource_bitset) &&
             manifest.resource(i).has_url()) {
           GURL url(manifest.resource(i).url());
           if (url.is_valid()) {
             double weight = ResourceWeight(
                 unfinished_work_->config_settings().resource_weight_function(),
                 manifest.resource(i).weight_ratio(), host_visits);
-            if (weight >= unfinished_work_->config_settings().min_weight())
+            if (weight >= unfinished_work_->config_settings().min_weight()) {
               resources_to_rank_.emplace_back(url, source.referrer(), weight);
+              ++num_included;

[bengr, 2017/02/24 21:04:13]

nit: I would be a bit clearer:
num_included -> included_resources_count
max_to_include -> maximum_included_resources_count
I'd also be ok with dropping the _count suffix.

[twifkak, 2017/02/24 21:35:55]

Done.

+            }
           }
         }
       }
       db_task_runner_->PostTask(
           FROM_HERE, base::Bind(&PrecacheDatabase::UpdatePrecacheReferrerHost,
                                 precache_database_, source.referrer(),
                                 manifest.id().id(), base::Time::Now()));
     }
   }
 
@@ skipping 72 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