Bug 1017291 - Keep track of the number of errors in AddIceCandidate before ICE completes, and record this number in telemetry in the success and failure cases separately. r=ekr

media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp

@@ -372,6 +372,7 @@ public:
         break;
 
       case ADDICECANDIDATEERROR:
+        mPC->OnAddIceCandidateError();
         mObserver->OnAddIceCandidateError(mCode, ObString(mReason.c_str()), rv);
         break;
 
@@ -493,6 +494,7 @@ PeerConnectionImpl::PeerConnectionImpl(const GlobalObject* aGlobal)
   , mNumAudioStreams(0)
   , mNumVideoStreams(0)
   , mHaveDataStream(false)
+  , mAddCandidateErrorCount(0)
   , mTrickle(true) // TODO(ekr@rtfm.com): Use pref
 {
 #ifdef MOZILLA_INTERNAL_API
@@ -1961,6 +1963,16 @@ PeerConnectionImpl::IceConnectionStateChange_m(PCImplIceConnectionState aState)
                               timeDelta.ToMilliseconds());
       }
     }
+
+    if (isSucceeded(aState)) {
+      Telemetry::Accumulate(
+          Telemetry::WEBRTC_ICE_ADD_CANDIDATE_ERRORS_GIVEN_SUCCESS,
+          mAddCandidateErrorCount);
+    } else if (isFailed(aState)) {
+      Telemetry::Accumulate(
+          Telemetry::WEBRTC_ICE_ADD_CANDIDATE_ERRORS_GIVEN_FAILURE,
+          mAddCandidateErrorCount);
+    }
   }
 #endif
 

media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.h

@@ -528,6 +528,10 @@ public:
   // is called to start the list over.
   void ClearSdpParseErrorMessages();
 
+  void OnAddIceCandidateError() {
+    ++mAddCandidateErrorCount;
+  }
+
   // Called to retreive the list of parsing errors.
   const std::vector<std::string> &GetSdpParseErrors();
 
@@ -707,6 +711,7 @@ private:
 
   // Holder for error messages from parsing SDP
   std::vector<std::string> mSDPParseErrorMessages;
+  unsigned int mAddCandidateErrorCount;
 
   bool mTrickle;
 

toolkit/components/telemetry/Histograms.json

@@ -5276,6 +5276,20 @@
     "n_buckets": "50",
     "description": "The number of calls made during a session."
   },
+  "WEBRTC_ICE_ADD_CANDIDATE_ERRORS_GIVEN_SUCCESS": {
+    "expires_in_version": "never",
+    "kind": "linear",
+    "high": "30",
+    "n_buckets": "29",
+    "description": "The number of times AddIceCandidate failed on a given PeerConnection, given that ICE succeeded."
+  },
+  "WEBRTC_ICE_ADD_CANDIDATE_ERRORS_GIVEN_FAILURE": {
+    "expires_in_version": "never",
+    "kind": "linear",
+    "high": "30",
+    "n_buckets": "29",
+    "description": "The number of times AddIceCandidate failed on a given PeerConnection, given that ICE failed."
+  },
   "DEVTOOLS_DEBUGGER_RDP_LOCAL_TRACERDETACH_MS": {
     "expires_in_version": "never",
     "kind": "exponential",