Take 2 at implementing activeTab.

chrome/browser/extensions/script_badge_controller.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 "chrome/browser/extensions/script_badge_controller.h"
 
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/ui/tab_contents/tab_contents.h"
 #include "chrome/common/extensions/extension.h"
@@ skipping 71 matching lines @@
       extension_id,
       callback);
 
   script_executor_.ExecuteScript(extension_id,
                                  script_type,
                                  code,
                                  frame_scope,
                                  run_at,
                                  world_type,
                                  this_callback);
-
 }
 
 void ScriptBadgeController::OnExecuteScriptFinished(
     const std::string& extension_id,
     const ExecuteScriptCallback& callback,
     bool success,
     int32 page_id,
     const std::string& error) {
   if (success && page_id == GetPageID()) {
     extensions_executing_scripts_.insert(extension_id);
@@ skipping 40 matching lines @@
   if (page_id == GetPageID()) {
     size_t original_size = extensions_executing_scripts_.size();
     extensions_executing_scripts_.insert(extension_ids.begin(),
                                          extension_ids.end());
     if (extensions_executing_scripts_.size() > original_size)
       Notify();
   }
 }
 
 }  // namespace extensions