Avoid overflow in NetEq's TimeStretch::SpeechDetection

webrtc/modules/audio_coding/neteq/time_stretch.cc

Index: webrtc/modules/audio_coding/neteq/time_stretch.cc
diff --git a/webrtc/modules/audio_coding/neteq/time_stretch.cc b/webrtc/modules/audio_coding/neteq/time_stretch.cc
index 880b1f82ea595271ee0f92795f8a39542e5039f4..c96d165e743cc9ffec8ed013598299ef40a8c9c6 100644
--- a/webrtc/modules/audio_coding/neteq/time_stretch.cc
+++ b/webrtc/modules/audio_coding/neteq/time_stretch.cc
@@ -182,7 +182,8 @@ bool TimeStretch::SpeechDetection(int32_t vec1_energy, int32_t vec2_energy,
   // (vec1_energy + vec2_energy) / 16 <= peak_index * background_noise_energy.
   // The two sides of the inequality will be denoted |left_side| and
   // |right_side|.
-  int32_t left_side = (vec1_energy + vec2_energy) / 16;
+  int32_t left_side = rtc::saturated_cast<int32_t>(
+      (static_cast<int64_t>(vec1_energy) + vec2_energy) / 16);
   int32_t right_side;
   if (background_noise_.initialized()) {
     right_side = background_noise_.Energy(master_channel_);