Make UBSan warnings fatal and fix the existing ones

webrtc/modules/audio_processing/aecm/aecm_core_c.cc

Index: webrtc/modules/audio_processing/aecm/aecm_core_c.cc
diff --git a/webrtc/modules/audio_processing/aecm/aecm_core_c.cc b/webrtc/modules/audio_processing/aecm/aecm_core_c.cc
index 32f26569f86618cac35b1fa5779f51605c0d28e7..0ca29459398340158e87e8964b7a9c53273551f8 100644
--- a/webrtc/modules/audio_processing/aecm/aecm_core_c.cc
+++ b/webrtc/modules/audio_processing/aecm/aecm_core_c.cc
@@ -24,6 +24,7 @@ extern "C" {
 }
 
 #include "webrtc/rtc_base/checks.h"
+#include "webrtc/rtc_base/safe_conversions.h"
 #include "webrtc/typedefs.h"
 
 // Square root of Hanning window in Q14.
@@ -452,7 +453,8 @@ int WebRtcAecm_ProcessBlock(AecmCore* aecm,
     // Far end signal through channel estimate in Q8
     // How much can we shift right to preserve resolution
     tmp32no1 = echoEst32[i] - aecm->echoFilt[i];
-    aecm->echoFilt[i] += (tmp32no1 * 50) >> 8;
+    aecm->echoFilt[i] += rtc::dchecked_cast<int32_t>(
+        (int64_t{tmp32no1} * 50) >> 8);
 
     zeros32 = WebRtcSpl_NormW32(aecm->echoFilt[i]) + 1;
     zeros16 = WebRtcSpl_NormW16(supGain) + 1;