Increase number of bits for trace buffer chunk index

Increase number of bits for trace buffer chunk index

The buffer for "record-as-much-as-possible" mode contains too many
chunks whose chunk indices to be contained in the 16 bit chunk index.

Increase chunk index to 26 bits.

BUG=516056
R=brianderson@chromium.org
TBR=dsinclair@chromium.org,nduca@chromium.org
TEST=Compile time static_asserts

Committed: https://crrev.com/0ba996473f611b4557ceb5162501dd0251f2d236
Cr-Commit-Position: refs/heads/master@{#342495}

[Xianzhu, 2015-08-07 19:56:44]

wangxianzhu@chromium.org changed reviewers:
+ dsinclair@chromium.org, nduca@chromium.org

[brianderson, 2015-08-07 23:31:19]

brianderson@chromium.org changed reviewers:
+ brianderson@chromium.org

[brianderson, 2015-08-07 23:31:19]

lgtm, but I'm just pixel wrangling today and not an owner.

Should we TBR this? It would go a long way in reducing the redness on the GPU
try bots.

[Xianzhu, 2015-08-07 23:59:24]

The CQ bit was checked by wangxianzhu@chromium.org

[commit-bot: I haz the power, 2015-08-07 23:59:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1276163003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1276163003/20001

[commit-bot: I haz the power, 2015-08-08 00:56:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-08 00:56:38]

Patchset 2 (id:??) landed as
https://crrev.com/0ba996473f611b4557ceb5162501dd0251f2d236
Cr-Commit-Position: refs/heads/master@{#342495}