Remove dead extensions tracking code.

extensions/browser/api/declarative_webrequest/webrequest_rules_registry.cc

 // Copyright (c) 2012 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 "extensions/browser/api/declarative_webrequest/webrequest_rules_registry.h"
 
 #include <algorithm>
 #include <limits>
 #include <utility>
 
@@ skipping 200 matching lines @@
   for (const IdRulePair& id_rule_pair : new_webrequest_rules) {
     const linked_ptr<const WebRequestRule>& rule = id_rule_pair.second;
     rule->conditions().GetURLMatcherConditionSets(&all_new_condition_sets);
     if (rule->conditions().HasConditionsWithoutUrls())
       rules_with_untriggered_conditions_.insert(rule.get());
   }
   url_matcher_.AddConditionSets(all_new_condition_sets);
 
   ClearCacheOnNavigation();
 
-  if (browser_context_ && !registered_rules.empty()) {
-    content::BrowserThread::PostTask(
-        content::BrowserThread::UI, FROM_HERE,
-        base::Bind(&extension_web_request_api_helpers::NotifyWebRequestAPIUsed,
-                   browser_context_, extension->id()));
-  }
-
   return std::string();
 }
 
 std::string WebRequestRulesRegistry::RemoveRulesImpl(
     const std::string& extension_id,
     const std::vector<std::string>& rule_identifiers) {
   // URLMatcherConditionSet IDs that can be removed from URLMatcher.
   std::vector<URLMatcherConditionSet::ID> remove_from_url_matcher;
   RulesMap& registered_rules = webrequest_rules_[extension_id];
 
@@ skipping 143 matching lines @@
   for (url_matcher::URLMatcherConditionSet::ID url_match : url_matches) {
     RuleTriggers::const_iterator rule_trigger = rule_triggers_.find(url_match);
     CHECK(rule_trigger != rule_triggers_.end());
     if (!base::ContainsKey(*result, rule_trigger->second) &&
         rule_trigger->second->conditions().IsFulfilled(url_match, request_data))
       result->insert(rule_trigger->second);
   }
 }
 
 }  // namespace extensions