Enable generation of local host candidate.

Source/modules/mediastream/RTCPeerConnection.cpp

Index: Source/modules/mediastream/RTCPeerConnection.cpp
diff --git a/Source/modules/mediastream/RTCPeerConnection.cpp b/Source/modules/mediastream/RTCPeerConnection.cpp
index b3ae4317d8a5817b673b7bd3035222e7243f6680..f68455d803fe916ebdc0d454a8aa06baab86343e 100644
--- a/Source/modules/mediastream/RTCPeerConnection.cpp
+++ b/Source/modules/mediastream/RTCPeerConnection.cpp
@@ -103,17 +103,28 @@ RTCConfiguration* RTCPeerConnection::parseConfiguration(const Dictionary& config
     }
 
     ArrayValue iceServers;
+    size_t numberOfServers = 0;
+    bool createIceServerArray = true;
     bool ok = DictionaryHelper::get(configuration, "iceServers", iceServers);
-    if (!ok || iceServers.isUndefinedOrNull()) {
-        exceptionState.throwTypeError("Malformed RTCConfiguration");
-        return 0;
-    }
-
-    size_t numberOfServers;
-    ok = iceServers.length(numberOfServers);
     if (!ok) {
-        exceptionState.throwTypeError("Malformed RTCConfiguration");
-        return 0;
+        v8::Local<v8::Value> iceServersValue;
+        // Failed to parse iceServers as ArrayValue, try it as a scalar.
+        ok = DictionaryHelper::get(configuration, "iceServers", iceServersValue);
+        if (!ok || iceServersValue->IsUndefined()) {
+            // if iceServers is not specified (|ok| is false) or specified as
+            // "undefined", treat it as the special case which RTCIceServerArray
+            // will not be created.
+            createIceServerArray = false;
+        } else {
+            exceptionState.throwTypeError("Malformed RTCConfiguration");
+            return 0;
+        }
+    } else {
+        ok = iceServers.length(numberOfServers);
+        if (!ok) {

[tommi (sloooow) - chröme, 2015/09/16 06:19:27]

do we need to handle numberOfServers == 0? (looks like that wasn't done before,
so this might be OK as is, but I'm wondering if you need both numberOfServers
and createIceServerArray or if one of them is enough)

[guoweis_left_chromium, 2015/09/16 17:29:05]

numberOfServers == 0, i.e. iceServers:[], is treated as a way to not cause local
host candidate generated.

[tommi (sloooow) - chröme, 2015/09/16 18:19:45]

ok, but whenever numberOfServers is 0, won't (or should) createIceServerArray be
false?  (and when it's != 0, then createIceServerArray will be true).  Not a big
issue, I'm just wondering if we need two variables for this.

[guoweis_left_chromium, 2015/09/16 22:10:20]

when there is no iceServers specified (or undefined), we want
createiceServerArray to be false. When there is iceServers, we want it to be
true. However, when we do have iceServers but the length is 0, (iceServers:[]),
we still want createiceServerArray to true. I think we still need 2 variables.

+            exceptionState.throwTypeError("Malformed RTCConfiguration");
+            return 0;
+        }
     }

[pthatcher2, 2015/09/16 04:09:58]

Can you put the early returns first?

if (DictionaryHelper::get(configuration, "iceServers", iceServers)) {
  ok = iceServers.length(numberOfServers)
  if (!ok) {
    exceptionState.throwTypeError("Malformed RTCConfiguration");
    return 0;
  )
} else {
  v8::Local<v8::Value> iceServersValue;
  ok = (!DictionaryHelper::get(configuration, "iceServers", iceServersValue)
           || iceServersValue->IsUndefined()); 
  if (!ok) {
    exceptionState.throwTypeError("Malformed RTCConfiguration");
    return 0;    
  }
  createIceServerArray = false;
}

[guoweis_left_chromium, 2015/09/16 17:29:05]

Done.

 
     RTCBundlePolicy bundlePolicy = RTCBundlePolicyBalanced;
@@ -144,6 +155,9 @@ RTCConfiguration* RTCPeerConnection::parseConfiguration(const Dictionary& config
     rtcConfiguration->setIceTransports(iceTransports);
     rtcConfiguration->setBundlePolicy(bundlePolicy);
     rtcConfiguration->setRtcpMuxPolicy(rtcpMuxPolicy);
+    if (createIceServerArray) {
+        rtcConfiguration->setIceServers(RTCIceServerArray::create());
+    }
 
     for (size_t i = 0; i < numberOfServers; ++i) {
         Dictionary iceServer;
@@ -191,7 +205,7 @@ RTCConfiguration* RTCPeerConnection::parseConfiguration(const Dictionary& config
                 return 0;
             }
 
-            rtcConfiguration->appendServer(RTCIceServer::create(url, username, credential));
+            rtcConfiguration->iceServers()->appendServer(RTCIceServer::create(url, username, credential));
         }
     }