Revert of Remove RTPPayloadStrategy and simplify RTPPayloadRegistry

webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h

Index: webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h
diff --git a/webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h b/webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h
index 668fe876f2e326b90b2ea118d7e99918ef68180f..8f9d5829f9cc066c0416d991994205af4d38fe24 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h
@@ -25,24 +25,46 @@
 struct CodecInst;
 class VideoCodec;
 
-// TODO(magjed): Remove once external code is updated.
+// This strategy deals with the audio/video-specific aspects
+// of payload handling.
 class RTPPayloadStrategy {
  public:
-  static RTPPayloadStrategy* CreateStrategy(bool handling_audio) {
-    return nullptr;
-  }
+  virtual ~RTPPayloadStrategy() {}
+
+  virtual bool CodecsMustBeUnique() const = 0;
+
+  virtual bool PayloadIsCompatible(const RtpUtility::Payload& payload,
+                                   uint32_t frequency,
+                                   size_t channels,
+                                   uint32_t rate) const = 0;
+
+  virtual void UpdatePayloadRate(RtpUtility::Payload* payload,
+                                 uint32_t rate) const = 0;
+
+  virtual RtpUtility::Payload* CreatePayloadType(const char* payload_name,
+                                                 int8_t payload_type,
+                                                 uint32_t frequency,
+                                                 size_t channels,
+                                                 uint32_t rate) const = 0;
+
+  virtual int GetPayloadTypeFrequency(
+      const RtpUtility::Payload& payload) const = 0;
+
+  static RTPPayloadStrategy* CreateStrategy(bool handling_audio);
+
+ protected:
+  RTPPayloadStrategy() {}
 };
 
 class RTPPayloadRegistry {
  public:
-  RTPPayloadRegistry();
+  // The registry takes ownership of the strategy.
+  explicit RTPPayloadRegistry(RTPPayloadStrategy* rtp_payload_strategy);
   ~RTPPayloadRegistry();
-  // TODO(magjed): Remove once external code is updated.
-  explicit RTPPayloadRegistry(RTPPayloadStrategy* rtp_payload_strategy)
-      : RTPPayloadRegistry() {}
 
   // TODO(magjed): Split RTPPayloadRegistry into separate Audio and Video class
-  // and simplify the code. http://crbug/webrtc/6743.
+  // and remove RTPPayloadStrategy, RTPPayloadVideoStrategy,
+  // RTPPayloadAudioStrategy, and simplify the code. http://crbug/webrtc/6743.
   int32_t RegisterReceivePayload(const CodecInst& audio_codec,
                                  bool* created_new_payload_type);
   int32_t RegisterReceivePayload(const VideoCodec& video_codec);
@@ -96,9 +118,13 @@
   // Returns true if the new media payload type has not changed.
   bool ReportMediaPayloadType(uint8_t media_payload_type);
 
-  int8_t red_payload_type() const { return GetPayloadTypeWithName("red"); }
+  int8_t red_payload_type() const {
+    rtc::CritScope cs(&crit_sect_);
+    return red_payload_type_;
+  }
   int8_t ulpfec_payload_type() const {
-    return GetPayloadTypeWithName("ulpfec");
+    rtc::CritScope cs(&crit_sect_);
+    return ulpfec_payload_type_;
   }
   int8_t last_received_payload_type() const {
     rtc::CritScope cs(&crit_sect_);
@@ -117,17 +143,34 @@
   RTC_DEPRECATED void set_use_rtx_payload_mapping_on_restore(bool val) {}
 
  private:
+  int32_t RegisterReceivePayload(const char* payload_name,
+                                 int8_t payload_type,
+                                 uint32_t frequency,
+                                 size_t channels,
+                                 uint32_t rate,
+                                 bool* created_new_payload_type);
+
+  int32_t ReceivePayloadType(const char* payload_name,
+                             uint32_t frequency,
+                             size_t channels,
+                             uint32_t rate,
+                             int8_t* payload_type) const;
+
   // Prunes the payload type map of the specific payload type, if it exists.
   void DeregisterAudioCodecOrRedTypeRegardlessOfPayloadType(
-      const CodecInst& audio_codec);
+      const char* payload_name,
+      size_t payload_name_length,
+      uint32_t frequency,
+      size_t channels,
+      uint32_t rate);
 
   bool IsRtxInternal(const RTPHeader& header) const;
-  // Returns the payload type for the payload with name |payload_name|, or -1 if
-  // no such payload is registered.
-  int8_t GetPayloadTypeWithName(const char* payload_name) const;
 
   rtc::CriticalSection crit_sect_;
-  std::map<int, RtpUtility::Payload> payload_type_map_;
+  RtpUtility::PayloadTypeMap payload_type_map_;
+  std::unique_ptr<RTPPayloadStrategy> rtp_payload_strategy_;
+  int8_t red_payload_type_;
+  int8_t ulpfec_payload_type_;
   int8_t incoming_payload_type_;
   int8_t last_received_payload_type_;
   int8_t last_received_media_payload_type_;