Disable extension auto-updating (hopefully temporarily)

We may need to make a few changes before we're ready for this to be live,
so we're disabling for now.

BUG=12117
TEST=none


Review URL: http://codereview.chromium.org/155388

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20433 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/profile.cc

@@ -560,7 +560,7 @@ void ProfileImpl::InitExtensions() {
       GetPath().AppendASCII(ExtensionsService::kInstallDirectoryName),
       MessageLoop::current(),
       g_browser_process->file_thread()->message_loop(),
-      true);
+      false);
 
   extensions_service_->Init();
 }