Change instant event phase name from i to I

Change instant event phase name from i to I

This matches current definition in the design doc[1] and unifies phase name between Chromium and Blink. Telemetry already expects both "i" and "I" values [2].

It used to be "I" in Chromium but it was changed in https://chromiumcodereview.appspot.com/12252058/

[1] https://docs.google.com/a/chromium.org/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/edit#
[2] https://code.google.com/p/chromium/codesearch#chromium/src/tools/telemetry/telemetry/timeline/trace_event_importer.py&q=%22elif%20phase%20==%20'I'%20or%20phase%20==%20'i':%22&sq=package:chromium&type=cs&l=252

BUG=None

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284644

[yurys, 2014-07-21 14:14:52]

@dsinclair: please take a look. Alternatively I can change this on Blink side to
use "i" (https://codereview.chromium.org/408443002/) but "I" seems more
consistent with other phase names.

[dsinclair, 2014-07-21 14:30:43]

lgtm

[commit-bot: I haz the power, 2014-07-21 14:31:42]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yurys@chromium.org/399423005/1

[commit-bot: I haz the power, 2014-07-21 15:54:46]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  ios_dbg_simulator on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_dbg_simulator/bui...)

[commit-bot: I haz the power, 2014-07-21 15:57:16]

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

[commit-bot: I haz the power, 2014-07-21 15:57:17]

Try jobs failed on following builders:
  ios_dbg_simulator on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_dbg_simulator/bui...)

[yurys, 2014-07-22 07:01:19]

The CQ bit was checked by yurys@chromium.org

[commit-bot: I haz the power, 2014-07-22 07:01:34]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yurys@chromium.org/399423005/1

[commit-bot: I haz the power, 2014-07-22 07:19:30]

Change committed as 284644