Improve activity log ad metrics

chrome/browser/extensions/active_script_controller.cc

 // Copyright 2014 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 "chrome/browser/extensions/active_script_controller.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
@@ skipping 78 matching lines @@
   PendingRequestList& list = pending_requests_[extension->id()];
   list.push_back(PendingRequest(callback, page_id));
 
   // If this was the first entry, notify the location bar that there's a new
   // icon.
   if (list.size() == 1u)
     LocationBarController::NotifyChange(web_contents());
 }
 
 void ActiveScriptController::OnAdInjectionDetected(
-    const std::vector<std::string> ad_injectors) {
+    const std::set<std::string> ad_injectors) {
   // We're only interested in data if there are ad injectors detected.
   if (ad_injectors.empty())
     return;
 
   size_t num_preventable_ad_injectors =
       base::STLSetIntersection<std::set<std::string> >(
           ad_injectors, permitted_extensions_).size();
 
   UMA_HISTOGRAM_COUNTS_100(
       "Extensions.ActiveScriptController.PreventableAdInjectors",
@@ skipping 120 matching lines @@
     UMA_HISTOGRAM_COUNTS_100(
         "Extensions.ActiveScriptController.PermittedExtensions",
         permitted_extensions_.size());
     UMA_HISTOGRAM_COUNTS_100(
         "Extensions.ActiveScriptController.DeniedExtensions",
         pending_requests_.size());
   }
 }
 
 }  // namespace extensions