WebRtcIlbcfix_Smooth: Fix UBSan fuzzer bug (left shift of 1 by 31 overflows)

WebRtcIlbcfix_Smooth: Fix UBSan fuzzer bug (left shift of 1 by 31 overflows)

scale1 == 31 if and only if w10 == 0. So even though 1 << scale1
overflows, we know that the result of the multiplication should be 0.
Handle that case.

BUG=chromium:615818
Committed: https://crrev.com/7f82fc988ded707247f317019215e4abdd6fe19f
Cr-Commit-Position: refs/heads/master@{#13847}

[kwiberg-webrtc, 2016-08-17 17:40:42]

kwiberg@webrtc.org changed reviewers:
+ tina.legrand@webrtc.org

[tlegrand-webrtc, 2016-08-22 13:13:39]

lgtm

[kwiberg-webrtc, 2016-08-22 13:16:31]

The CQ bit was checked by kwiberg@webrtc.org

[commit-bot: I haz the power, 2016-08-22 13:16:37]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-08-22 14:43:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-22 14:43:57]

Description was changed from

==========
WebRtcIlbcfix_Smooth: Fix UBSan fuzzer bug (left shift of 1 by 31 overflows)

scale1 == 31 if and only if w10 == 0. So even though 1 << scale1
overflows, we know that the result of the multiplication should be 0.
Handle that case.

BUG=chromium:615818
==========

to

==========
WebRtcIlbcfix_Smooth: Fix UBSan fuzzer bug (left shift of 1 by 31 overflows)

scale1 == 31 if and only if w10 == 0. So even though 1 << scale1
overflows, we know that the result of the multiplication should be 0.
Handle that case.

BUG=chromium:615818

Committed: https://crrev.com/7f82fc988ded707247f317019215e4abdd6fe19f
Cr-Commit-Position: refs/heads/master@{#13847}
==========

[commit-bot: I haz the power, 2016-08-22 14:44:01]

Patchset 1 (id:??) landed as
https://crrev.com/7f82fc988ded707247f317019215e4abdd6fe19f
Cr-Commit-Position: refs/heads/master@{#13847}