Add promise-based addIceCandidate, setLocalDescription and setRemoteDescription to RTCPeerConnection

third_party/WebKit/Source/modules/mediastream/MediaErrorState.cpp

Index: third_party/WebKit/Source/modules/mediastream/MediaErrorState.cpp
diff --git a/third_party/WebKit/Source/modules/mediastream/MediaErrorState.cpp b/third_party/WebKit/Source/modules/mediastream/MediaErrorState.cpp
index e52cb024b24b232a91e2dc1463b408fd14639a1d..1d341df0df2ac6c1697e3c45d17dda9a0c00f195 100644
--- a/third_party/WebKit/Source/modules/mediastream/MediaErrorState.cpp
+++ b/third_party/WebKit/Source/modules/mediastream/MediaErrorState.cpp
@@ -99,6 +99,29 @@ void MediaErrorState::raiseException(ExceptionState& target)
     }
 }
 
+String MediaErrorState::getErrorMessage()
+{
+    switch (m_errorType) {
+    case NoError:
+        ASSERT_NOT_REACHED();
+        break;
+    case TypeError:
+    case DOMError:
+        return m_message;
+        break;
+    case ConstraintError:
+        // This is for the cases where we can't pass back a
+        // NavigatorUserMediaError.
+        // So far, we have this in the constructor of RTCPeerConnection,
+        // which is due to be deprecated.
+        // TODO(hta): Remove this code. https://crbug.com/576581
+        return String("Unsatisfiable constraint " + m_constraint);
+        break;
+    }
+
+    return String();
+}
+
 NavigatorUserMediaError* MediaErrorState::createError()
 {
     ASSERT(m_errorType == ConstraintError);