Reland of move ignored return code from modules. (patchset #1 id:1 of https://codereview.webrtc.org/1736663004/ )

Reason for revert:
Revert breaks other uses, a fix will be rolled into Chromium instead.

Original issue's description:
> Revert of Remove ignored return code from modules. (patchset #3 id:40001 of https://codereview.webrtc.org/1703833002/ )
>
> Reason for revert:
> Breaks Chromium.
>
> Original issue's description:
> > Remove ignored return code from modules.
> >
> > ModuleProcessImpl doesn't act on return codes and having them around is
> > confusing (it's unclear what an error return code here would do even).
> >
> > BUG=
> > R=tommi@webrtc.org
> >
> > Committed: https://chromium.googlesource.com/external/webrtc/+/f14c47a58cb2a333cb9b11aef593f0e632fdb28a
>
> TBR=tommi@webrtc.org,pbos@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/da33a8a2a22f6d19ba2a8cce963beafbdbaa8fd8
> Cr-Commit-Position: refs/heads/master@{#11761}

TBR=tommi@webrtc.org,torbjorng@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.webrtc.org/1737013002

Cr-Commit-Position: refs/heads/master@{#11762}
diff --git a/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc b/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
index 72a5ff5..bf60878 100644
--- a/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
+++ b/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
@@ -162,16 +162,15 @@
       kBitrateControllerUpdateIntervalMs - time_since_update_ms, 0);
 }
 
-int32_t BitrateControllerImpl::Process() {
+void BitrateControllerImpl::Process() {
   if (TimeUntilNextProcess() > 0)
-    return 0;
+    return;
   {
     rtc::CritScope cs(&critsect_);
     bandwidth_estimation_.UpdateEstimate(clock_->TimeInMilliseconds());
   }
   MaybeTriggerOnNetworkChanged();
   last_bitrate_update_ms_ = clock_->TimeInMilliseconds();
-  return 0;
 }
 
 void BitrateControllerImpl::OnReceivedRtcpReceiverReport(