Fix some clang warnings with -Wmissing-braces in WebRTC.

Fix some clang warnings with -Wmissing-braces in WebRTC.

Clang warns if there are missing braces around a subobject
initializer. The most common idiom that triggers this is:
  STRUCT s = {0};
if the first field of STRUCT is itself a struct. This can
be more simply written as:
  STRUCT s = {};
which also prevents the warning from firing.

Other instances of the warning have been fixed by adding
braces where appropriate.

BUG=505297
TBR=jiayl@webrtc.org

Committed: https://crrev.com/a771bf8ee84f293c166d3e377d852e9705c12725
Cr-Commit-Position: refs/heads/master@{#9529}

[dcheng, 2015-07-01 07:38:09]

dcheng@chromium.org changed reviewers:
+ henrika@webrtc.org, jiayl@webrtc.org

[dcheng, 2015-07-01 07:38:09]

+henrika for base and system_wrappers changes
+jiayl for modules/desktop_capture changes

[dcheng, 2015-07-01 07:55:30]

dcheng@chromium.org changed reviewers:
+ henrikg@webrtc.org
- henrika@webrtc.org

[dcheng, 2015-07-01 07:55:30]

+henrikg, mind taking a look at the base/system_wrappers changes?

[Henrik Grunell WebRTC, 2015-07-01 08:39:20]

lgtm

[jiayl, 2015-07-01 18:50:16]

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

[jiayl, 2015-07-01 18:50:16]

lgtm

[dcheng, 2015-07-01 18:50:40]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-07-01 18:51:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216353002/1

[commit-bot: I haz the power, 2015-07-01 18:52:00]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-01 18:52:02]

Exceeded global retry quota

[dcheng, 2015-07-01 19:40:59]

The CQ bit was checked by dcheng@chromium.org

[dcheng, 2015-07-01 19:40:59]

The patchset sent to the CQ was uploaded after l-g-t-m from henrikg@webrtc.org,
jiayl@chromium.org
Link to the patchset: https://codereview.chromium.org/1216353002/#ps20001
(title: "rebase?")

[commit-bot: I haz the power, 2015-07-01 19:41:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216353002/20001

[commit-bot: I haz the power, 2015-07-01 19:55:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-01 19:55:40]

Exceeded global retry quota

[jiayl, 2015-07-01 20:56:32]

The CQ bit was checked by jiayl@chromium.org

[commit-bot: I haz the power, 2015-07-01 20:56:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216353002/20001

[commit-bot: I haz the power, 2015-07-01 20:58:22]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-01 20:58:23]

Exceeded global retry quota

[dcheng, 2015-07-01 23:10:52]

The CQ bit was checked by dcheng@chromium.org

[dcheng, 2015-07-01 23:10:52]

The patchset sent to the CQ was uploaded after l-g-t-m from henrikg@webrtc.org,
jiayl@chromium.org
Link to the patchset: https://codereview.chromium.org/1216353002/#ps40001
(title: "Fix paths, maybe")

[commit-bot: I haz the power, 2015-07-01 23:11:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216353002/40001

[commit-bot: I haz the power, 2015-07-01 23:17:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-01 23:17:50]

Try jobs failed on following builders:
  presubmit on tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/presubmit/builds/81)

[dcheng, 2015-07-01 23:22:16]

The CQ bit was checked by dcheng@chromium.org

[dcheng, 2015-07-01 23:22:16]

TBR jiayl@webrtc.org (jiayl@chromium.org LGTMed)

[commit-bot: I haz the power, 2015-07-01 23:22:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216353002/40001

[commit-bot: I haz the power, 2015-07-02 00:52:16]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-07-02 00:52:27]

Patchset 3 (id:??) landed as
https://crrev.com/a771bf8ee84f293c166d3e377d852e9705c12725
Cr-Commit-Position: refs/heads/master@{#9529}