[net] Make HostResolverImpl::OnIPAddressChange faster by removing blocking on HaveOnlyLoopbackAddre…

[net] Make HostResolverImpl::OnIPAddressChange faster by removing blocking on HaveOnlyLoopbackAddresses.

Also simplify HostResolverImpl::IPv6ProbeJob by using MessageLoop::PostTaskAndReply with a WeakPtr.

BUG=157933
TEST=manual, disable/enable network connection


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=166150

[szym, 2012-11-01 16:29:33]

The situation is a bit wasteful because the initial call to ProbeIPv6Support
invokes OnIPAddressChanged which will abandon the first LoopbackProbeJob and
start a new one.

ProbeIPv6Support is exposed primarily for net-internals. If we didn't need the
"Run IPv6 Probe" button, we would be able to pass the default_address_family_
parameter as part of HostResolver::Options.

[eroman, 2012-11-03 00:56:55]

lgtm

http://codereview.chromium.org/11359007/diff/14/net/base/host_resolver_impl.cc
File net/base/host_resolver_impl.cc (right):

http://codereview.chromium.org/11359007/diff/14/net/base/host_resolver_impl.c...
net/base/host_resolver_impl.cc:938: : public
base::RefCountedThreadSafe<HostResolverImpl::LoopbackProbeJob> {
you may consider not making this refcounted anymore. Instead the
PostTaskAndReply() could Own() this in the reply callback.

http://codereview.chromium.org/11359007/diff/14/net/base/host_resolver_impl.c...
net/base/host_resolver_impl.cc:1845: OnIPAddressChanged();
This has the sideffect of cancelling all current requests, is that desired?

[szym, 2012-11-05 23:08:04]

http://codereview.chromium.org/11359007/diff/14/net/base/host_resolver_impl.cc
File net/base/host_resolver_impl.cc (right):

http://codereview.chromium.org/11359007/diff/14/net/base/host_resolver_impl.c...
net/base/host_resolver_impl.cc:938: : public
base::RefCountedThreadSafe<HostResolverImpl::LoopbackProbeJob> {
On 2012/11/03 00:56:55, eroman wrote:
> you may consider not making this refcounted anymore. Instead the
> PostTaskAndReply() could Own() this in the reply callback.

I forgot about this option. Thanks!

http://codereview.chromium.org/11359007/diff/14/net/base/host_resolver_impl.c...
net/base/host_resolver_impl.cc:1845: OnIPAddressChanged();
On 2012/11/03 00:56:55, eroman wrote:
> This has the sideffect of cancelling all current requests, is that desired?

I've realized that when |ipv6_probe_monitoring_ == false| we can just ignore the
output of the current probe job. I removed the trigger from here and added a
check to IPv6ProbeSetDefaultAddressFamily.

[commit-bot: I haz the power, 2012-11-06 03:39:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/szym@chromium.org/11359007/10005

[commit-bot: I haz the power, 2012-11-06 04:44:19]

Change committed as 166150