Disable logging of failed SPDY PINGs in a timemax bucket, and update histogram bucketing strategy f…

Disable logging of failed SPDY PINGs in a timemax bucket, and update histogram bucketing strategy for Net.SpdyPing.RTT to match the strategy of Net.TCP_Connection_Latency.
* timemax is int64max, whereas histograms use int values, so this doesn't end up working well and can break certain analysis operations such as computing the average SPDY PING time. Additionally, counts for failed SPDY PINGs are recorded in the Net.SpdySession.ClosedOnError enum histogram, so there's no need for us to log them in a special bucket in the RTT histo as well.
* Also change the histogram bucketing strategy for Net.SpdyPing.RTT to match the strategy of Net.TCP_Connection_Latency since these are measuring similar things and it's useful to be able to compare TCP RTTs with application-layer RTTs.

BUG=475129
Committed: https://crrev.com/4ce665a95aeacb2bf1c83e110784226cc2536cc2
Cr-Commit-Position: refs/heads/master@{#324318}

[Bryan McQuade, 2015-04-08 18:38:03]

bmcquade@chromium.org changed reviewers:
+ rch@chromium.org

[Bryan McQuade, 2015-04-08 18:46:00]

The CQ bit was checked by bmcquade@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-04-08 18:47:25]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1074523002/1

[commit-bot: I haz the power, 2015-04-08 18:47:26]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-08 18:47:27]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Ryan Hamilton, 2015-04-08 21:37:03]

The CQ bit was checked by rch@chromium.org

[Ryan Hamilton, 2015-04-08 21:37:04]

lgtm

[commit-bot: I haz the power, 2015-04-08 21:37:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1074523002/1

[commit-bot: I haz the power, 2015-04-09 00:44:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-09 00:44:57]

Patchset 1 (id:??) landed as
https://crrev.com/4ce665a95aeacb2bf1c83e110784226cc2536cc2
Cr-Commit-Position: refs/heads/master@{#324318}