Fix error when accumulating floats in an int.

webrtc/modules/audio_processing/level_controller/level_controller.cc

Index: webrtc/modules/audio_processing/level_controller/level_controller.cc
diff --git a/webrtc/modules/audio_processing/level_controller/level_controller.cc b/webrtc/modules/audio_processing/level_controller/level_controller.cc
index bd8d439874899321035a00dfccc16614555a965e..a9fed9bf95ab04a9a0a6843e0616eb40e9034204 100644
--- a/webrtc/modules/audio_processing/level_controller/level_controller.cc
+++ b/webrtc/modules/audio_processing/level_controller/level_controller.cc
@@ -35,7 +35,7 @@ void UpdateAndRemoveDcLevel(float forgetting_factor,
                             rtc::ArrayView<float> x) {
   RTC_DCHECK(!x.empty());
   float mean =
-      std::accumulate(x.begin(), x.end(), 0) / static_cast<float>(x.size());
+      std::accumulate(x.begin(), x.end(), 0.0f) / static_cast<float>(x.size());
   *dc_level += forgetting_factor * (mean - *dc_level);
 
   for (float& v : x) {