Remove SendPacer from ViEEncoder and make sure SendPacer starts at a valid bitrate

This reverts commit e30c27205148b34ba421184efe65f6a0780b436d (https://codereview.webrtc.org/1958053002/)

Original reverted cl is in patch set #1.
Changes in following patch sets.

The cl now also make sure SendPacer starts with the configured bitrate provided in a call to CongestionController::SetBweBitrates)()

It turns out that the failing tests in 609816 is due to a bug in the current code that runs the proper at 300kbit regardless of configured start bitrate.

Original cl description:
Remove SendPacer from ViEEncoder
This CL moves the logic where the ViEEncoder pause if the pacer is full to the BitrateController. If the queue is full, the controller reports a bitrate of zero to  Call (and BitrateAllocator)

BUG=chromium:609816, webrtc:5687
TBR=mflodman@webrtc.org
NOTRY=True  // Due to bug  in android_x86 cq builder....

Review-Url: https://codereview.webrtc.org/1958113003
Cr-Commit-Position: refs/heads/master@{#12688}
diff --git a/webrtc/modules/modules.gyp b/webrtc/modules/modules.gyp
index 921697e..4365c65 100644
--- a/webrtc/modules/modules.gyp
+++ b/webrtc/modules/modules.gyp
@@ -270,6 +270,7 @@
             'audio_processing/vad/voice_activity_detector_unittest.cc',
             'bitrate_controller/bitrate_controller_unittest.cc',
             'bitrate_controller/send_side_bandwidth_estimation_unittest.cc',
+            'congestion_controller/congestion_controller_unittest.cc',
             'media_file/media_file_unittest.cc',
             'module_common_types_unittest.cc',
             'pacing/bitrate_prober_unittest.cc',