Strict Overflow Prevention video_capture_oracle.cc

Strict Overflow Prevention video_capture_oracle.cc
Adding check to video_capture_oracle.cc that prevents strict overflow
warning/error.

BUG=

Committed: https://crrev.com/916455eb7da1baf9d50ebe0400b086a3d795a09b
Cr-Commit-Position: refs/heads/master@{#341808}

[esum, 2015-08-04 15:03:31]

esum@chromium.org changed reviewers:
+ miu@chromium.org

[esum, 2015-08-04 15:03:31]

Hi Yuri,

Thank you again for your help yesterday.

I consulted erickung@ and lcwu@ (cc'd) about the strict-overflow error that we
were seeing, and they came up with a modification that builds and allows the
compiler on our eureka bots to deduce that signed overflow is not possible.

Please have a look and let us know what you think.

Thanks.

[miu, 2015-08-04 20:40:55]

lgtm.  I suppose all this really means I should have made frame_number an
unsigned type.  ;-)

[miu, 2015-08-04 20:41:04]

The CQ bit was checked by miu@chromium.org

[commit-bot: I haz the power, 2015-08-04 20:42:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1263273003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1263273003/20001

[commit-bot: I haz the power, 2015-08-04 22:11:57]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-04 22:12:28]

Patchset 2 (id:??) landed as
https://crrev.com/916455eb7da1baf9d50ebe0400b086a3d795a09b
Cr-Commit-Position: refs/heads/master@{#341808}