cc: Send updated tile priority with tiles into tracing.

cc: Send updated tile priority with tiles into tracing.

This patch adds a combined_priority field to tracing which contains
the up-to-date combined priority for the tile. I plan on removing the
active/pending priorities from traces, since they typically do not
provide any useful information (and are likely to be out of date).

R=danakj, enne

Committed: https://crrev.com/dcf21da68106fb041650dabf3f65d77927cb4779
Cr-Commit-Position: refs/heads/master@{#321827}

[vmpstr, 2015-03-20 00:19:52]

Please take a look.

[enne (OOO), 2015-03-23 18:19:44]

The CQ bit was checked by enne@chromium.org

[enne (OOO), 2015-03-23 18:19:45]

lgtm

[commit-bot: I haz the power, 2015-03-23 18:19:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1027563003/1

[commit-bot: I haz the power, 2015-03-23 19:16:49]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-23 19:17:45]

Patchset 1 (id:??) landed as
https://crrev.com/dcf21da68106fb041650dabf3f65d77927cb4779
Cr-Commit-Position: refs/heads/master@{#321827}