[soup] session cookies are not correctly reported in getRawCookies()
https://bugs.webkit.org/show_bug.cgi?id=111584

Reviewed by Martin Robinson.

As per libsoup documentation, SoupCookie->expires is NULL for session cookies.
However, the soup implementation for getRawCookies() does not check for NULL
case before passing the value to soup_date_to_time_t(), which leads to run time
warnings.

We should also pass true for WebCore::Cookie's session argument if
SoupCookie->expires is NULL. The current implementation reports the cookie as a
session one if soup_cookie_jar_is_persistent(jar) returns true, which is
inaccurate.

No new tests, no behavior change for layout tests as Web Inspector currently
ignores the "session" member and uses expires/max-age instead to deduce it.

* platform/network/soup/CookieJarSoup.cpp:
(WebCore::getRawCookies):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144936 268f45cc-cd09-0410-ab3c-d52691b4dbfc