Remove camera.setPreviewTexture in doStopCaptureOnCameraThread.

Removes camera.setPreviewTexture in doStopCaptureOnCameraThread and removes the try catch statement since the only method throwing an exception was setPreviewTexture.

BUG=webrtc:5003
R=magjed@webrtc.org

Committed: https://crrev.com/3520f9e0493b106d71cae3ee67108e00af13f1f7
Cr-Commit-Position: refs/heads/master@{#9985}

[perkj_webrtc, 2015-09-17 19:54:31]

Patchset #2 (id:20001) has been deleted

[perkj_webrtc, 2015-09-17 19:54:56]

perkj@webrtc.org changed reviewers:
+ magjed@webrtc.org

[perkj_webrtc, 2015-09-17 19:54:57]

Is there a bug number I should add?

[magjed_webrtc, 2015-09-18 08:45:15]

lgtm

[perkj_webrtc, 2015-09-18 08:45:47]

The CQ bit was checked by perkj@webrtc.org

[commit-bot: I haz the power, 2015-09-18 08:45:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354683004/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354683004/60001

[perkj_webrtc, 2015-09-18 09:53:05]

Committed patchset #3 (id:60001) manually as
3520f9e0493b106d71cae3ee67108e00af13f1f7 (presubmit successful).

[commit-bot: I haz the power, 2015-09-18 09:53:06]

Patchset 3 (id:??) landed as
https://crrev.com/3520f9e0493b106d71cae3ee67108e00af13f1f7
Cr-Commit-Position: refs/heads/master@{#9985}