Rent-A-Codec: Reference count the shared iSAC bandwidth estimation state

webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h

Index: webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h
diff --git a/webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h b/webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h
index 6bb32c99ed965145c0259f96fc04006bf2acb6e7..1ab5ae9d639a8f50a1b1a0fb4b2bddb09431bcb4 100644
--- a/webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h
+++ b/webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h
@@ -11,6 +11,7 @@
 #ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_ISAC_LOCKED_BANDWIDTH_INFO_H_
 #define WEBRTC_MODULES_AUDIO_CODING_CODECS_ISAC_LOCKED_BANDWIDTH_INFO_H_
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/modules/audio_coding/codecs/isac/bandwidth_info.h"
@@ -34,7 +35,18 @@ class LockedIsacBandwidthInfo final {
     bwinfo_ = bwinfo;
   }
 
+  int AddRef() const { return rtc::AtomicOps::Increment(&ref_count_); }
+
+  int Release() const {
+    const int count = rtc::AtomicOps::Decrement(&ref_count_);
+    if (count == 0) {
+      delete this;
+    }
+    return count;
+  }
+
  private:
+  mutable volatile int ref_count_;
   rtc::CriticalSection lock_;
   IsacBandwidthInfo bwinfo_ GUARDED_BY(lock_);
 };