Update APM config on RuntimeSetting pre amplifier gain change

Bug: webrtc:11045
Change-Id: I78c777632a46e1f8ebf96f4a64c4e1738184d350
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158081
Reviewed-by: Per Ã…hgren <peah@webrtc.org>
Commit-Queue: Sam Zackrisson <saza@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29586}
diff --git a/modules/audio_processing/audio_processing_impl.cc b/modules/audio_processing/audio_processing_impl.cc
index c4ef3b2..ca6edfe 100644
--- a/modules/audio_processing/audio_processing_impl.cc
+++ b/modules/audio_processing/audio_processing_impl.cc
@@ -944,6 +944,7 @@
         if (config_.pre_amplifier.enabled) {
           float value;
           setting.GetFloat(&value);
+          config_.pre_amplifier.fixed_gain_factor = value;
           submodules_.pre_amplifier->SetGainFactor(value);
         }
         // TODO(bugs.chromium.org/9138): Log setting handling by Aec Dump.