Add ANGLE platform tracing methods.

Add ANGLE platform tracing methods.

This enables event tracing in ANGLE via the new APIs. This can
replace the old methods via SetTraceFunctionPointers.

BUG=436191
Committed: https://crrev.com/5eef409e3a90d4e71515338270269a7b13226f50
Cr-Commit-Position: refs/heads/master@{#324232}

[Jamie Madill, 2015-04-07 21:16:25]

jmadill@chromium.org changed reviewers:
+ kbr@chromium.org

[Jamie Madill, 2015-04-07 21:16:46]

PTAL, still need to do a bit of manual re-testing.

[Ken Russell (switch to Gerrit), 2015-04-07 22:01:02]

lgtm

[Jamie Madill, 2015-04-08 16:05:49]

Verified manually that the D3D9 startup trace still works.

[Jamie Madill, 2015-04-08 16:05:52]

The CQ bit was checked by jmadill@chromium.org

[commit-bot: I haz the power, 2015-04-08 16:07:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1064163002/1

[commit-bot: I haz the power, 2015-04-08 16:33:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-08 16:34:21]

Patchset 1 (id:??) landed as
https://crrev.com/5eef409e3a90d4e71515338270269a7b13226f50
Cr-Commit-Position: refs/heads/master@{#324232}