Revert of Remove ignored return code from modules.

webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
index 7f33bc2ee57c1dc2b44aeade3feaaaf87f8072a2..07889f9eca5b82ede8e9d7ac5f07aed5a0e42728 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
@@ -118,7 +118,7 @@
 }
 
 // Process any pending tasks such as timeouts (non time critical events).
-void ModuleRtpRtcpImpl::Process() {
+int32_t ModuleRtpRtcpImpl::Process() {
   const int64_t now = clock_->TimeInMilliseconds();
   last_process_time_ = now;
 
@@ -202,6 +202,7 @@
     // A receiver has timed out
     rtcp_receiver_.UpdateTMMBR();
   }
+  return 0;
 }
 
 void ModuleRtpRtcpImpl::SetRtxSendStatus(int mode) {