Fix compile on ChromeOS. Revert "File browser: de-singleton"

This reverts commit 7db4f5b43aba588022cbc3c182f539da8cdbfa03.

BUG=none
TEST=none
TBR=asargent

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90482 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 1a65255..f734a66 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -645,6 +645,13 @@
     ExternalExtensionProviderInterface* provider = i->get();
     provider->ServiceShutdown();
   }
+
+#if defined(OS_CHROMEOS)
+  if (event_routers_initialized_) {
+    ExtensionFileBrowserEventRouter::GetInstance()->
+        StopObservingFileSystemEvents();
+  }
+#endif
 }
 
 void ExtensionService::InitEventRouters() {
@@ -670,9 +677,9 @@
   web_navigation_event_router_->Init();
 
 #if defined(OS_CHROMEOS)
-  file_browser_event_router_.reset(
-      new ExtensionFileBrowserEventRouter(profile_));
-  file_browser_event_router_->Init();
+  ExtensionFileBrowserEventRouter::GetInstance()->ObserveFileSystemEvents(
+      profile_);
+  ExtensionMediaPlayerEventRouter::GetInstance()->Init(profile_);
 #endif
 
 #if defined(OS_CHROMEOS) && defined(TOUCH_UI)