Enforce LGTM from owners of depends-on paths in DEPS via presubmit.

This presubmit check has been copied from Chromium's PRESUBMIT.py [1].

Example of the error message:

** Presubmit ERRORS **
You need LGTM from owners of depends-on paths in DEPS that were modified in this CL:
    '+third_party/protobuf/src/google/protobuf',

Suggested missing target path OWNERS:
...

[1] - https://cs.chromium.org/chromium/src/PRESUBMIT.py?l=1475-1550&rcl=57cc805bba436b3f26b86168628a343be8abe2a3

Bug: webrtc:9453
Change-Id: Icc028bcd1d48b83f2f31bb821c708289eebd8623
Reviewed-on: https://webrtc-review.googlesource.com/95885
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24891}
diff --git a/ENG_REVIEW_OWNERS b/ENG_REVIEW_OWNERS
new file mode 100644
index 0000000..de5f240
--- /dev/null
+++ b/ENG_REVIEW_OWNERS
@@ -0,0 +1,11 @@
+# Current list of eng reviewers mostly for the purpose of reviewing
+# dependencies on third-party directories (because //ENG_REVIEW_OWNERS is
+# included by //third_party/OWNERS).
+
+# People listed in this file will only have to coordinate with chromium's eng
+# review owners to ensure that the added dependency was OK.
+
+danilchap@webrtc.org
+kwiberg@webrtc.org
+mbonadei@webrtc.org
+phoglund@webrtc.org