Fix uninitialized read from Worker::ns_channel_initialized_.
Fix uninitialized read from Worker::ns_channel_initialized_.

BUG=http://code.google.com/p/nativeclient/issues/detail?id=2226
TEST=run chrome_browser_tests under Memcheck
Review URL: http://codereview.chromium.org/7827010

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@6607 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client