When measuring waste in the DNS resolver related to AF_UNSPEC lookups, also

When measuring waste in the DNS resolver related to AF_UNSPEC lookups, also
measure when we could be combining jobs.

BUG=139811
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=151710

[pauljensen, 2012-08-14 19:55:21]

Please review my rewrite of the DNS histogram to measure waste related to
merging IPv4 and UNSPEC lookups.  The rewrite now measures cache and job
duplication.

[szym, 2012-08-14 22:05:03]

Just a few minor issues, but lgtm already.

https://chromiumcodereview.appspot.com/10824297/diff/1/net/base/host_resolver...
File net/base/host_resolver_impl.cc (right):

https://chromiumcodereview.appspot.com/10824297/diff/1/net/base/host_resolver...
net/base/host_resolver_impl.cc:1670: bool found_other_family_cache = false,
found_other_family_job = false;
nit: Although I can't find anything explicit in the code style, I suggest one
variable per declaration.

https://chromiumcodereview.appspot.com/10824297/diff/1/net/base/host_resolver...
net/base/host_resolver_impl.cc:1675: found_other_family_job =
jobs_.find(other_family_key) != jobs_.end();
I suggest |jobs_.count(other_family_key) > 0|

https://chromiumcodereview.appspot.com/10824297/diff/1/net/base/host_resolver...
net/base/host_resolver_impl.cc:1677: enum {  // Used in HISTOGRAM_ENUMERATION.
nit: UMA_HISTOGRAM_ENUMERATION

https://chromiumcodereview.appspot.com/10824297/diff/1/net/base/host_resolver...
net/base/host_resolver_impl.cc:1683: AF_WASTE_MISS_IPV4,
How about AF_WASTE_NONE_* to indicate that there is no waste in this case?

https://chromiumcodereview.appspot.com/10824297/diff/1/net/base/host_resolver...
net/base/host_resolver_impl.cc:1696:
UMA_HISTOGRAM_ENUMERATION("DNS.ResolveUnspecWasteCategory", category,
nit: I don't think you need "Category". "Waste" seems sufficiently specific.

[commit-bot: I haz the power, 2012-08-15 13:44:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pauljensen@chromium.org/10824297/3002

[commit-bot: I haz the power, 2012-08-15 14:59:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pauljensen@chromium.org/10824297/9001

[commit-bot: I haz the power, 2012-08-15 17:16:11]

Change committed as 151710