Refactor: Simplify WaitableEventWatcher.

content/browser/plugin_service_impl.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 "content/browser/plugin_service_impl.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/file_path.h"
@@ skipping 151 matching lines @@
 void PluginServiceImpl::StartWatchingPlugins() {
   // Start watching for changes in the plugin list. This means watching
   // for changes in the Windows registry keys and on both Windows and POSIX
   // watch for changes in the paths that are expected to contain plugins.
 #if defined(OS_WIN)
   if (hkcu_key_.Create(HKEY_CURRENT_USER,
                        webkit::npapi::kRegistryMozillaPlugins,
                        KEY_NOTIFY) == ERROR_SUCCESS) {
     if (hkcu_key_.StartWatching() == ERROR_SUCCESS) {
       hkcu_event_.reset(new base::WaitableEvent(hkcu_key_.watch_event()));
-      hkcu_watcher_.StartWatching(hkcu_event_.get(), this);
+      if (registry_watcher_callback_.is_null())
+        registry_watcher_callback_ =
+            base::Bind(&PluginServiceImpl::OnWaitableEventSignaled,
+                       base::Unretained(this));
+      hkcu_watcher_.StartWatching(hkcu_event_.get(),
+                                  &registry_watcher_callback_);
     }
   }
   if (hklm_key_.Create(HKEY_LOCAL_MACHINE,
                        webkit::npapi::kRegistryMozillaPlugins,
                        KEY_NOTIFY) == ERROR_SUCCESS) {
     if (hklm_key_.StartWatching() == ERROR_SUCCESS) {
       hklm_event_.reset(new base::WaitableEvent(hklm_key_.watch_event()));
-      hklm_watcher_.StartWatching(hklm_event_.get(), this);
+      if (registry_watcher_callback_.is_null())
+        registry_watcher_callback_ =
+            base::Bind(&PluginServiceImpl::OnWaitableEventSignaled,
+                       base::Unretained(this));
+      hklm_watcher_.StartWatching(hklm_event_.get(),
+                                  &registry_watcher_callback_);
     }
   }
 #endif
 #if defined(OS_POSIX) && !defined(OS_OPENBSD) && !defined(OS_ANDROID)
 // On ChromeOS the user can't install plugins anyway and on Windows all
 // important plugins register themselves in the registry so no need to do that.
 
   // Get the list of all paths for registering the FilePathWatchers
   // that will track and if needed reload the list of plugins on runtime.
   std::vector<FilePath> plugin_dirs;
@@ skipping 512 matching lines @@
 void PluginServiceImpl::GetInternalPlugins(
     std::vector<webkit::WebPluginInfo>* plugins) {
   plugin_list_->GetInternalPlugins(plugins);
 }
 
 webkit::npapi::PluginList* PluginServiceImpl::GetPluginList() {
   return plugin_list_;
 }
 
 }  // namespace content