Implementation of Extension Updater.

This also contains changes to the ExtensionsService to hook up the ExtensionUpdater. 

BUG=http://crbug.com/12117
TEST=Extensions still work


Review URL: http://codereview.chromium.org/149213

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20379 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index 085f8146..df95acf 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -565,7 +565,8 @@
       GetPrefs(),
       GetPath().AppendASCII(ExtensionsService::kInstallDirectoryName),
       MessageLoop::current(),
-      g_browser_process->file_thread()->message_loop());
+      g_browser_process->file_thread()->message_loop(),
+      true);
 
   extensions_service_->Init();
 }