Added a query function for whether submodules are enabled

that can be called from the render side without making APM
singlethreaded.

This CL is addressing the problems with high render-side
call duration that were triggered by the CL
https://codereview.webrtc.org/1844583003

BUG=webrtc:5736

Review URL: https://codereview.webrtc.org/1859243002

Cr-Commit-Position: refs/heads/master@{#12266}

webrtc/modules/audio_processing/gain_control_impl.cc

@@ -310,6 +310,12 @@ int GainControlImpl::Enable(bool enable) {
   return AudioProcessing::kNoError;
 }
 
+bool GainControlImpl::is_enabled_render_side_query() const {
+  // TODO(peah): Add threadchecker.
+  rtc::CritScope cs(crit_render_);
+  return enabled_;
+}
+
 bool GainControlImpl::is_enabled() const {
   rtc::CritScope cs(crit_capture_);
   return enabled_;