UMA histogram: Corrects misspelled histogram name

UMA histogram: Corrects misspelled histogram name

The UMA stat WebRTC.AecDelayBasedQuality was not logged due to a misspelling.

Correct name https://code.google.com/p/chromium/codesearch#chromium/src/tools/metrics/histograms/histograms.xml&q=AecDelay&sq=package:chromium&type=cs&l=41307

BUG=N/A
TBR=perkj@chromium.org

Committed: https://crrev.com/38adc026ac37019bf16c5f227976af645ce1532b
Cr-Commit-Position: refs/heads/master@{#313050}

[bjornv, 2015-01-23 14:23:59]

The CQ bit was checked by bjornv@chromium.org

[commit-bot: I haz the power, 2015-01-23 14:25:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/867233002/1

[commit-bot: I haz the power, 2015-01-23 14:25:11]

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

[commit-bot: I haz the power, 2015-01-23 14:25:12]

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.

[bjornv, 2015-01-23 14:37:49]

Per, PTAL at this tiny CL

[perkj_chrome, 2015-01-26 09:03:59]

The CQ bit was checked by perkj@chromium.org

[perkj_chrome, 2015-01-26 09:04:00]

lgtm

[commit-bot: I haz the power, 2015-01-26 09:04:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/867233002/1

[commit-bot: I haz the power, 2015-01-26 09:07:06]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-26 09:08:45]

Patchset 1 (id:??) landed as
https://crrev.com/38adc026ac37019bf16c5f227976af645ce1532b
Cr-Commit-Position: refs/heads/master@{#313050}