Reland Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.

webrtc/media/base/rtpdataengine.cc

Index: webrtc/media/base/rtpdataengine.cc
diff --git a/webrtc/media/base/rtpdataengine.cc b/webrtc/media/base/rtpdataengine.cc
index 705ccbdaff771842e3838c6a0341299145541690..ae3617455573754271c16d94dcd6125083aaa991 100644
--- a/webrtc/media/base/rtpdataengine.cc
+++ b/webrtc/media/base/rtpdataengine.cc
@@ -10,7 +10,7 @@
 
 #include "webrtc/media/base/rtpdataengine.h"
 
-#include "webrtc/base/buffer.h"
+#include "webrtc/base/copyonwritebuffer.h"
 #include "webrtc/base/helpers.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/ratelimiter.h"
@@ -205,9 +205,9 @@ bool RtpDataMediaChannel::RemoveRecvStream(uint32_t ssrc) {
 }
 
 void RtpDataMediaChannel::OnPacketReceived(
-    rtc::Buffer* packet, const rtc::PacketTime& packet_time) {
+    rtc::CopyOnWriteBuffer* packet, const rtc::PacketTime& packet_time) {
   RtpHeader header;
-  if (!GetRtpHeader(packet->data(), packet->size(), &header)) {
+  if (!GetRtpHeader(packet->cdata(), packet->size(), &header)) {
     // Don't want to log for every corrupt packet.
     // LOG(LS_WARNING) << "Could not read rtp header from packet of length "
     //                 << packet->length() << ".";
@@ -215,7 +215,7 @@ void RtpDataMediaChannel::OnPacketReceived(
   }
 
   size_t header_length;
-  if (!GetRtpHeaderLen(packet->data(), packet->size(), &header_length)) {
+  if (!GetRtpHeaderLen(packet->cdata(), packet->size(), &header_length)) {
     // Don't want to log for every corrupt packet.
     // LOG(LS_WARNING) << "Could not read rtp header"
     //                 << length from packet of length "
@@ -223,7 +223,7 @@ void RtpDataMediaChannel::OnPacketReceived(
     return;
   }
   const char* data =
-      packet->data<char>() + header_length + sizeof(kReservedSpace);
+      packet->cdata<char>() + header_length + sizeof(kReservedSpace);
   size_t data_len = packet->size() - header_length - sizeof(kReservedSpace);
 
   if (!receiving_) {
@@ -276,7 +276,7 @@ bool RtpDataMediaChannel::SetMaxSendBandwidth(int bps) {
 
 bool RtpDataMediaChannel::SendData(
     const SendDataParams& params,
-    const rtc::Buffer& payload,
+    const rtc::CopyOnWriteBuffer& payload,
     SendDataResult* result) {
   if (result) {
     // If we return true, we'll set this to SDR_SUCCESS.
@@ -329,7 +329,7 @@ bool RtpDataMediaChannel::SendData(
   rtp_clock_by_send_ssrc_[header.ssrc]->Tick(
       now, &header.seq_num, &header.timestamp);
 
-  rtc::Buffer packet(kMinRtpPacketLen, packet_len);
+  rtc::CopyOnWriteBuffer packet(kMinRtpPacketLen, packet_len);
   if (!SetRtpHeader(packet.data(), packet.size(), header)) {
     return false;
   }