Revert of Merge webrtc/video_engine/ into webrtc/video/ (patchset #2 id:20001 of https://codereview.webrtc.org/1506773002/ )

Reason for revert:
Breaks Dr Memory Light https://build.chromium.org/p/client.webrtc/builders/Win%20DrMemory%20Light/builds/4643 and all the Android Tests bots.

Original issue's description:
> Merge webrtc/video_engine/ into webrtc/video/
>
> BUG=webrtc:1695
> R=mflodman@webrtc.org
>
> Committed: https://crrev.com/03ef053202bc5d5ab43460eebf5403232f157646
> Cr-Commit-Position: refs/heads/master@{#10926}

TBR=mflodman@webrtc.org,pbos@webrtc.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:1695

Review URL: https://codereview.webrtc.org/1507903005

Cr-Commit-Position: refs/heads/master@{#10937}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index ddbf71a..60323c8 100755
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -19,6 +19,7 @@
   'webrtc/audio',
   'webrtc/call',
   'webrtc/modules/video_processing',
+  'webrtc/video_engine',
 ]
 
 # List of directories of "supported" native APIs. That means changes to headers