InjectedScriptManager::CallbackData should be disposed when an associated worker thread terminates

CallbackData created by InjectedScriptManager should be deleted when
an associated worker thread terminates. The most straightforward way
to do that is to make the InjectedScriptManager hold a list of
OwnPtr<CallbackData> that the InjectedScriptManager created.
Since the the InjectedScriptManager is destructed in ~WorkerScriptController(), it's guaranteed that all associated CallbackData is destructed
in
~WorkerScriptController() as well.

This change will fix a couple of inspector-protocol/debugger tests in oilpan builds.

BUG=398472

Review URL: https://codereview.chromium.org/452043002

git-svn-id: svn://svn.chromium.org/blink/trunk@179905 bbb929c8-8fbe-4397-9dbb-9b2b20218538