Deprecate EventFactory and delete all usage.

Will be deleted as soon as downstream calls of
VideoCodingModule::Create are updated.

Tbr: sprang@webrtc.org  # Trivial change in video/
Bug: webrtc:3380
Change-Id: Iaeb6da2fb68991225fe9086ddddd4a553e1620b4
Reviewed-on: https://webrtc-review.googlesource.com/c/107890
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25554}

modules/video_coding/receiver_unittest.cc

@@ -30,7 +30,7 @@ class TestVCMReceiver : public ::testing::Test {
   TestVCMReceiver()
       : clock_(new SimulatedClock(0)),
         timing_(clock_.get()),
-        receiver_(&timing_, clock_.get(), nullptr) {
+        receiver_(&timing_, clock_.get()) {
     stream_generator_.reset(
         new StreamGenerator(0, clock_->TimeInMilliseconds()));
   }