AcmReceiver: Ask NetEq to delete all decoders at once instead of one by one

It requires a new NetEq method, but it can no longer fail. And we no
longer need to use AcmReceiver::decoders_, which we're trying to
eliminate.

(This is a re-land of https://codereview.webrtc.org/2342313002.)

BUG=webrtc:5801

Review-Url: https://codereview.webrtc.org/2348233002
Cr-Commit-Position: refs/heads/master@{#14304}

webrtc/modules/audio_coding/neteq/decoder_database.cc

@@ -169,6 +169,12 @@ int DecoderDatabase::Remove(uint8_t rtp_payload_type) {
   return kOK;
 }
 
+void DecoderDatabase::RemoveAll() {
+  decoders_.clear();
+  active_decoder_type_ = -1;      // No active decoder.
+  active_cng_decoder_type_ = -1;  // No active CNG decoder.
+}
+
 const DecoderDatabase::DecoderInfo* DecoderDatabase::GetDecoderInfo(
     uint8_t rtp_payload_type) const {
   DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);

webrtc/modules/audio_coding/neteq/decoder_database.h

@@ -136,6 +136,9 @@ class DecoderDatabase {
   // Returns kDecoderNotFound or kOK depending on the outcome of the operation.
   virtual int Remove(uint8_t rtp_payload_type);
 
+  // Remove all entries.
+  virtual void RemoveAll();
+
   // Returns a pointer to the DecoderInfo struct for |rtp_payload_type|. If
   // no decoder is registered with that |rtp_payload_type|, NULL is returned.
   virtual const DecoderInfo* GetDecoderInfo(uint8_t rtp_payload_type) const;

webrtc/modules/audio_coding/neteq/decoder_database_unittest.cc

@@ -47,6 +47,21 @@ TEST(DecoderDatabase, InsertAndRemove) {
   EXPECT_TRUE(db.Empty());
 }
 
+TEST(DecoderDatabase, InsertAndRemoveAll) {
+  DecoderDatabase db(new rtc::RefCountedObject<MockAudioDecoderFactory>);
+  const std::string kCodecName1 = "Robert\'); DROP TABLE Students;";
+  const std::string kCodecName2 = "https://xkcd.com/327/";
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(0, NetEqDecoder::kDecoderPCMu, kCodecName1));
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(1, NetEqDecoder::kDecoderPCMa, kCodecName2));
+  EXPECT_EQ(2, db.Size());
+  EXPECT_FALSE(db.Empty());
+  db.RemoveAll();
+  EXPECT_EQ(0, db.Size());
+  EXPECT_TRUE(db.Empty());
+}
+
 TEST(DecoderDatabase, GetDecoderInfo) {
   rtc::scoped_refptr<MockAudioDecoderFactory> factory(
       new rtc::RefCountedObject<MockAudioDecoderFactory>);

webrtc/modules/audio_coding/neteq/include/neteq.h

@@ -183,6 +183,9 @@ class NetEq {
   // -1 on failure.
   virtual int RemovePayloadType(uint8_t rtp_payload_type) = 0;
 
+  // Removes all payload types from the codec database.
+  virtual void RemoveAllPayloadTypes() = 0;
+
   // Sets a minimum delay in millisecond for packet buffer. The minimum is
   // maintained unless a higher latency is dictated by channel condition.
   // Returns true if the minimum is successfully applied, otherwise false is

webrtc/modules/audio_coding/neteq/mock/mock_decoder_database.h

@@ -42,6 +42,7 @@ class MockDecoderDatabase : public DecoderDatabase {
                    AudioDecoder* decoder));
   MOCK_METHOD1(Remove,
       int(uint8_t rtp_payload_type));
+  MOCK_METHOD0(RemoveAll, void());
   MOCK_CONST_METHOD1(GetDecoderInfo,
       const DecoderInfo*(uint8_t rtp_payload_type));
   MOCK_CONST_METHOD1(GetRtpPayloadType,

webrtc/modules/audio_coding/neteq/neteq_impl.cc

@@ -293,6 +293,11 @@ int NetEqImpl::RemovePayloadType(uint8_t rtp_payload_type) {
   return kFail;
 }
 
+void NetEqImpl::RemoveAllPayloadTypes() {
+  rtc::CritScope lock(&crit_sect_);
+  decoder_database_->RemoveAll();
+}
+
 bool NetEqImpl::SetMinimumDelay(int delay_ms) {
   rtc::CritScope lock(&crit_sect_);
   if (delay_ms >= 0 && delay_ms < 10000) {

webrtc/modules/audio_coding/neteq/neteq_impl.h

@@ -123,6 +123,8 @@ class NetEqImpl : public webrtc::NetEq {
   // -1 on failure.
   int RemovePayloadType(uint8_t rtp_payload_type) override;
 
+  void RemoveAllPayloadTypes() override;
+
   bool SetMinimumDelay(int delay_ms) override;
 
   bool SetMaximumDelay(int delay_ms) override;

webrtc/modules/audio_coding/neteq/neteq_impl_unittest.cc

@@ -230,6 +230,12 @@ TEST_F(NetEqImplTest, RemovePayloadType) {
   EXPECT_EQ(NetEq::kFail, neteq_->RemovePayloadType(rtp_payload_type));
 }
 
+TEST_F(NetEqImplTest, RemoveAllPayloadTypes) {
+  CreateInstance();
+  EXPECT_CALL(*mock_decoder_database_, RemoveAll()).WillOnce(Return());
+  neteq_->RemoveAllPayloadTypes();
+}
+
 TEST_F(NetEqImplTest, InsertPacket) {
   CreateInstance();
   const size_t kPayloadLength = 100;