Initial support for built-in DNS resolver/cache.

Initial support for built-in DNS resolver/cache.

BUG=60149
TEST=None

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=64271

[agayev, 2010-10-28 15:23:40]

Same thing that got reverted, doing one more round of trybots before committing.

[eroman, 2011-01-10 20:13:45]

http://codereview.chromium.org/4216001/diff/6001/net/base/host_resolver_impl.cc
File net/base/host_resolver_impl.cc (right):

http://codereview.chromium.org/4216001/diff/6001/net/base/host_resolver_impl....
net/base/host_resolver_impl.cc:75: HostResolverProc* resolver_proc,
This change doesn't make sense to me.

The "CreateSystemHostResolver()" is supposed to be creating a host resolver that
uses the underlying system's getaddrinfo().

However if we pass in a custom HostResolverProc then that is not the case.

I don't think we should be adding an extra parameter to this function which will
always be NULL. Rather the one location(s) which want to create their custom
non-system host resolver should just call:

   new HostResolverImpl(resolver_proc, ....)

In fact for the feature you ware working on I think it should be implemented as
a separate HostResolver subclass alltogether, and not use a custom
HostResolverProc.

(The HostResolverProc were really just a feature for unit-tests, in order to
mock out the system dependency).