diff --git a/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc b/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
index eeb912a..cb7c418 100644
--- a/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
+++ b/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
@@ -118,16 +118,16 @@
 }  // namespace
 
 AcmReceiver::AcmReceiver(const AudioCodingModule::Config& config)
-    : id_(config.id),
-      neteq_(NetEq::Create(config.neteq_config)),
+    : crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),
+      id_(config.id),
       last_audio_decoder_(-1),  // Invalid value.
-      decode_lock_(RWLockWrapper::CreateRWLock()),
-      neteq_crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),
-      vad_enabled_(true),
       previous_audio_activity_(AudioFrame::kVadPassive),
       current_sample_rate_hz_(config.neteq_config.sample_rate_hz),
       nack_(),
       nack_enabled_(false),
+      neteq_(NetEq::Create(config.neteq_config)),
+      decode_lock_(RWLockWrapper::CreateRWLock()),
+      vad_enabled_(true),
       clock_(config.clock),
       av_sync_(false),
       initial_delay_manager_(),
@@ -150,7 +150,6 @@
 AcmReceiver::~AcmReceiver() {
   delete neteq_;
   delete decode_lock_;
-  delete neteq_crit_sect_;
 }
 
 int AcmReceiver::SetMinimumDelay(int delay_ms) {
@@ -164,7 +163,7 @@
   if (delay_ms < 0 || delay_ms > 10000) {
     return -1;
   }
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
 
   if (delay_ms == 0) {
     av_sync_ = false;
@@ -208,7 +207,7 @@
 }
 
 int AcmReceiver::current_sample_rate_hz() const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   return current_sample_rate_hz_;
 }
 
@@ -271,7 +270,7 @@
   const RTPHeader* header = &rtp_header.header;  // Just a shorthand.
 
   {
-    CriticalSectionScoped lock(neteq_crit_sect_);
+    CriticalSectionScoped lock(crit_sect_.get());
 
     int codec_id = RtpHeaderToCodecIndex(*header, incoming_payload);
     if (codec_id < 0) {
@@ -330,7 +329,7 @@
           rtp_header, receive_timestamp, packet_type, new_codec, sample_rate_hz,
           missing_packets_sync_stream_.get());
     }
-  }
+  }  // |crit_sect_| is released.
 
   {
     WriteLockScoped lock_codecs(*decode_lock_);  // Lock to prevent an encoding.
@@ -361,7 +360,7 @@
 
   {
     // Accessing members, take the lock.
-    CriticalSectionScoped lock(neteq_crit_sect_);
+    CriticalSectionScoped lock(crit_sect_.get());
 
     if (av_sync_) {
       assert(initial_delay_manager_.get());
@@ -406,7 +405,7 @@
   }
 
   // Accessing members, take the lock.
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
 
   // Update NACK.
   int decoded_sequence_num = 0;
@@ -501,7 +500,7 @@
     neteq_decoder = kDecoderOpus_2ch;
   }
 
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
 
   // The corresponding NetEq decoder ID.
   // If this coder has been registered before.
@@ -547,13 +546,13 @@
 
 void AcmReceiver::EnableVad() {
   neteq_->EnableVad();
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   vad_enabled_ = true;
 }
 
 void AcmReceiver::DisableVad() {
   neteq_->DisableVad();
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   vad_enabled_ = false;
 }
 
@@ -565,7 +564,7 @@
 // many as it can.
 int AcmReceiver::RemoveAllCodecs() {
   int ret_val = 0;
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   for (int n = 0; n < ACMCodecDB::kMaxNumCodecs; ++n) {
     if (decoders_[n].registered) {
       if (neteq_->RemovePayloadType(decoders_[n].payload_type) == 0) {
@@ -591,7 +590,7 @@
     LOG_FERR1(LS_ERROR, "AcmReceiver::RemoveCodec", payload_type);
     return -1;
   }
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   decoders_[codec_index].registered = false;
   if (last_audio_decoder_ == codec_index)
     last_audio_decoder_ = -1;  // Codec is removed, invalidate last decoder.
@@ -599,7 +598,7 @@
 }
 
 void AcmReceiver::set_id(int id) {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   id_ = id;
 }
 
@@ -614,12 +613,12 @@
 }
 
 int AcmReceiver::last_audio_codec_id() const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   return last_audio_decoder_;
 }
 
 int AcmReceiver::last_audio_payload_type() const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   if (last_audio_decoder_ < 0)
     return -1;
   assert(decoders_[last_audio_decoder_].registered);
@@ -627,7 +626,7 @@
 }
 
 int AcmReceiver::RedPayloadType() const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   if (ACMCodecDB::kRED < 0 ||
       !decoders_[ACMCodecDB::kRED].registered) {
     LOG_F(LS_WARNING) << "RED is not registered.";
@@ -637,7 +636,7 @@
 }
 
 int AcmReceiver::LastAudioCodec(CodecInst* codec) const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   if (last_audio_decoder_ < 0) {
     return -1;
   }
@@ -692,7 +691,7 @@
 
 int AcmReceiver::DecoderByPayloadType(uint8_t payload_type,
                                       CodecInst* codec) const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   int codec_index = PayloadType2CodecIndex(payload_type);
   if (codec_index < 0) {
     LOG_FERR1(LS_ERROR, "AcmReceiver::DecoderByPayloadType", payload_type);
@@ -718,7 +717,7 @@
   if (max_nack_list_size == 0 || max_nack_list_size > Nack::kNackListSizeLimit)
     return -1;
 
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   if (!nack_enabled_) {
     nack_.reset(Nack::Create(kNackThresholdPackets));
     nack_enabled_ = true;
@@ -734,14 +733,14 @@
 }
 
 void AcmReceiver::DisableNack() {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   nack_.reset();  // Memory is released.
   nack_enabled_ = false;
 }
 
 std::vector<uint16_t> AcmReceiver::GetNackList(
     int round_trip_time_ms) const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   if (round_trip_time_ms < 0) {
     WEBRTC_TRACE(webrtc::kTraceWarning, webrtc::kTraceAudioCoding, id_,
                  "GetNackList: round trip time cannot be negative."
@@ -757,7 +756,7 @@
 
 void AcmReceiver::ResetInitialDelay() {
   {
-    CriticalSectionScoped lock(neteq_crit_sect_);
+    CriticalSectionScoped lock(crit_sect_.get());
     av_sync_ = false;
     initial_delay_manager_.reset(NULL);
     missing_packets_sync_stream_.reset(NULL);
@@ -860,7 +859,7 @@
 
 void AcmReceiver::GetDecodingCallStatistics(
     AudioDecodingCallStats* stats) const {
-  CriticalSectionScoped lock(neteq_crit_sect_);
+  CriticalSectionScoped lock(crit_sect_.get());
   *stats = call_stats_.GetDecodingStatistics();
 }
 
diff --git a/webrtc/modules/audio_coding/main/acm2/acm_receiver.h b/webrtc/modules/audio_coding/main/acm2/acm_receiver.h
index 11440d1..b6898f7 100644
--- a/webrtc/modules/audio_coding/main/acm2/acm_receiver.h
+++ b/webrtc/modules/audio_coding/main/acm2/acm_receiver.h
@@ -23,6 +23,7 @@
 #include "webrtc/modules/audio_coding/neteq/interface/neteq.h"
 #include "webrtc/modules/interface/module_common_types.h"
 #include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/system_wrappers/interface/thread_annotations.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
@@ -327,7 +328,8 @@
  private:
   int PayloadType2CodecIndex(uint8_t payload_type) const;
 
-  bool GetSilence(int desired_sample_rate_hz, AudioFrame* frame);
+  bool GetSilence(int desired_sample_rate_hz, AudioFrame* frame)
+      EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
 
   int GetNumSyncPacketToInsert(uint16_t received_squence_number);
 
@@ -338,21 +340,23 @@
 
   void InsertStreamOfSyncPackets(InitialDelayManager::SyncStream* sync_stream);
 
-  int id_;
+  scoped_ptr<CriticalSectionWrapper> crit_sect_;
+  int id_;  // TODO(henrik.lundin) Make const.
+  int last_audio_decoder_ GUARDED_BY(crit_sect_);
+  AudioFrame::VADActivity previous_audio_activity_ GUARDED_BY(crit_sect_);
+  int current_sample_rate_hz_ GUARDED_BY(crit_sect_);
+  ACMResampler resampler_ GUARDED_BY(crit_sect_);
+  // Used in GetAudio, declared as member to avoid allocating every 10ms.
+  // TODO(henrik.lundin) Stack-allocate in GetAudio instead?
+  int16_t audio_buffer_[AudioFrame::kMaxDataSizeSamples] GUARDED_BY(crit_sect_);
+  scoped_ptr<Nack> nack_ GUARDED_BY(crit_sect_);
+  bool nack_enabled_ GUARDED_BY(crit_sect_);
+  CallStatistics call_stats_ GUARDED_BY(crit_sect_);
   NetEq* neteq_;
   Decoder decoders_[ACMCodecDB::kMaxNumCodecs];
-  int last_audio_decoder_;
   RWLockWrapper* decode_lock_;
-  CriticalSectionWrapper* neteq_crit_sect_;
   bool vad_enabled_;
-  AudioFrame::VADActivity previous_audio_activity_;
-  int current_sample_rate_hz_;
-  ACMResampler resampler_;
-  // Used in GetAudio, declared as member to avoid allocating every 10ms.
-  int16_t audio_buffer_[AudioFrame::kMaxDataSizeSamples];
-  scoped_ptr<Nack> nack_;
-  bool nack_enabled_;
-  Clock* clock_;
+  Clock* clock_;  // TODO(henrik.lundin) Make const if possible.
 
   // Indicates if a non-zero initial delay is set, and the receiver is in
   // AV-sync mode.
@@ -366,8 +370,6 @@
   // initial delay is set.
   scoped_ptr<InitialDelayManager::SyncStream> missing_packets_sync_stream_;
   scoped_ptr<InitialDelayManager::SyncStream> late_packets_sync_stream_;
-
-  CallStatistics call_stats_;
 };
 
 }  // namespace acm2