Fixing crash on chrome profiler on generating html trace.

Fixing crash on chrome profiler on generating html trace.

The chrome profiler opens file without utf-8 encoding, so the html
trace file was not getting generated. This CL changes the file opening
to have utf-8 encoding.

BUG=477295
Committed: https://crrev.com/723a007e43d66c624b6cff92f11b7e1ccab4b904
Cr-Commit-Position: refs/heads/master@{#325230}

[ssid, 2015-04-15 11:53:46]

ssid@chromium.org changed reviewers:
+ skyostil@chromium.org

[ssid, 2015-04-15 11:53:46]

Small fix, PTAL.

[Sami, 2015-04-15 12:02:38]

Thanks for the quick fix! lgtm.

[ssid, 2015-04-15 12:03:18]

The CQ bit was checked by ssid@chromium.org

[commit-bot: I haz the power, 2015-04-15 12:03:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1068693003/1

[commit-bot: I haz the power, 2015-04-15 12:29:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-15 12:30:32]

Patchset 1 (id:??) landed as
https://crrev.com/723a007e43d66c624b6cff92f11b7e1ccab4b904
Cr-Commit-Position: refs/heads/master@{#325230}