Fix a deadlock in ViEEncoder::DeliverFrame.
Fix a deadlock in ViEEncoder::DeliverFrame.

The deadlock can happen when using HW encoder. HW encoder calls
the encode complete callback on libjingle worker thread instead
of ViECaptureThread. The capture thread can hold VieEncoder::|data_cs_|
and wait for ModuleRtpRtcpImpl::|critical_section_module_ptrs_|.
When libjingle worker thread runs encode complete callback, it
can hold ModuleRtpRtcpImpl::|critical_section_module_ptrs_| and
wait for VieEncoder::|data_cs_|.

|default_rtp_rtcp_| is not guarded by |data_cs|. So move it out of
the critical section to avoid the deadlock.

BUG=chromium:352567
TEST=Run apprtc loopback on CrOS.
Run apprtc between CrOS and Linux.
Run vie_auto_test.

R=henrik.lundin@webrtc.org, pbos@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/10039004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: ac4b87c2588e4e2b51e0677849ed482ea490d30d

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