commit 2a27db26ffb757606b7e5b8a004c8134861fc175
author Eric Orth <ericorth@chromium.org> Wed Feb 06 16:24:43 2019
committer Commit Bot <commit-bot@chromium.org> Wed Feb 06 16:24:43 2019
tree d647f209fad6c33e60c35402cfc2af134bc0df2b
parent 190592543c43d8bf73d88bd679c4938f035a8c80

Rewrite StaleHostResolver around CreateRequest() API

Motivation is that HostResolver::Resolve() is soon to be deleted and
all usage converted to CreateRequest (or to network service APIs). Need
to ensure cronet/StaleHostResolver continue working during transition.

Fully implemented StaleHostResolver::CreateRequest().
StaleHostResolver::Resolve() now implemented using CreateRequest() and
HostResolver::ResolveLegacy().

As the new API is more focused on the ResolveHostRequest object, it
made more sense to convert the StaleHostResolver::RequestImpl to be a
direct implementation, rather than using a separate Handle. Main
difference is lifetime semantics. The object is now owned by the client
instead of self-destroying on completion.  Extra orphaned requests
(allowed to complete to backfill the cache) are then detached to be
owned by StaleHostResolver instance itself as the client will likely
destroy the request after getting results.

With added weak ptr back to StaleHostResolver, it became simpler to
have RequestImpl directly read options_ and implement the stale usable
checks rather than pass in a callback.

Bug: 922699
Change-Id: Iadb48c0d574cc47ff6f79a6d313164b126c1d76d
Reviewed-on: https://chromium-review.googlesource.com/c/1452699
Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Commit-Queue: Eric Orth <ericorth@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629601}