* Avoid doing concurrent DNS resolves of the same hostname in HostResolver.
* Add a 1 minute cache for host resolves.
* Refactor HostResolver to handle multiple requests.
* Make HostResolver a dependency of URLRequestContext. operate the HostResolver
in async mode for proxy resolver (bridging to IO thread).
TEST=unittests
BUG=13163
Review URL: http://codereview.chromium.org/118100
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18236 0039d316-1c4b-4281-b951-d872f2087c98
47 files changed
