Bug 1305813 - do not send empty StreamId;r=drno

Also moving RID (StreamID) storage to the stack to clear up the TODO item
and simplify the code.

When unset the StreamID is stored as an empty string.

Added missing GUARDED_BY on rid_

Added a check to shortcut checking strlen on the StreamId when it is an empty string (which is most of the time).

MozReview-Commit-ID: EPUlPNBXYsQ

--HG--
extra : rebase_source : 08e1b9ea796c991d141164424014d2311ff9341c

media/webrtc/trunk/webrtc/modules/rtp_rtcp/source/rtp_sender.cc

@@ -97,7 +97,7 @@ RTPSender::RTPSender(
       payload_type_(-1),
       payload_type_map_(),
       rtp_header_extension_map_(),
-      rid_(NULL),
+      rid_{0},
       packet_history_(clock),
       flexfec_packet_history_(clock),
       // Statistics
@@ -166,10 +166,6 @@ RTPSender::~RTPSender() {
     delete it->second;
     payload_type_map_.erase(it);
   }
-
-  if (rid_) {
-    delete[] rid_;
-  }
 }
 
 uint16_t RTPSender::ActualSendBitrateKbit() const {
@@ -200,13 +196,12 @@ uint32_t RTPSender::NackOverheadRate() const {
 
 int32_t RTPSender::SetRID(const char* rid) {
   rtc::CritScope lock(&send_critsect_);
-  // TODO(jesup) avoid allocations
-  if (!rid_ || strlen(rid_) < strlen(rid)) {
-    // rid rarely changes length....
-    delete [] rid_;
-    rid_ = new char[strlen(rid)+1];
+  const size_t len = rid ? strlen(rid) : 0;
+  if (!len || len >= sizeof(rid_)) {
+    rid_[0] = '\0';
+  } else {
+    memmove(&rid_[0], rid, len + 1);
   }
-  strcpy(rid_, rid);
   return 0;
 }
 
@@ -455,7 +450,7 @@ bool RTPSender::SendOutgoingData(FrameType frame_type,
     result = video_->SendVideo(video_type, frame_type, payload_type,
                                rtp_timestamp, capture_time_ms, payload_data,
                                payload_size, fragmentation, rtp_header,
-                               rid_);
+                               &rid_[0]);
   }
 
   rtc::CritScope cs(&statistics_crit_);

media/webrtc/trunk/webrtc/modules/rtp_rtcp/source/rtp_sender.h

@@ -280,7 +280,7 @@ class RTPSender {
 
   RtpHeaderExtensionMap rtp_header_extension_map_ GUARDED_BY(send_critsect_);
 
-  char* rid_;
+  char rid_[kRIDSize + 1] GUARDED_BY(send_critsect_);
 
   // Tracks the current request for playout delay limits from application
   // and decides whether the current RTP frame should include the playout

media/webrtc/trunk/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc

@@ -17,6 +17,7 @@
 #include <vector>
 #include <utility>
 
+#include "webrtc/common_types.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/trace_event.h"
@@ -324,8 +325,11 @@ bool RTPSenderVideo::SendVideo(RtpVideoCodecTypes video_type,
         rtp_header->SetExtension<VideoOrientation>(current_rotation);
       last_rotation_ = current_rotation;
     }
-    if (rid) {
-      rtp_header->SetExtensionWithLength<StreamId>(strlen(rid)-1, rid);
+    if (rid && rid[0]) {
+      const size_t len = strlen(rid);
+      if (len) {
+        rtp_header->SetExtensionWithLength<StreamId>(len - 1, rid);
+      }
     }
 
     // FEC settings.