Constraints: Make advanced list be a list.

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

Index: third_party/WebKit/Source/modules/mediastream/MediaConstraintsImpl.cpp
diff --git a/third_party/WebKit/Source/modules/mediastream/MediaConstraintsImpl.cpp b/third_party/WebKit/Source/modules/mediastream/MediaConstraintsImpl.cpp
index 24dcb6c445790f1526dedc10ca006eb63b491a97..1369ede6bf703245f5abbe2ff7f8edb68795ec2a 100644
--- a/third_party/WebKit/Source/modules/mediastream/MediaConstraintsImpl.cpp
+++ b/third_party/WebKit/Source/modules/mediastream/MediaConstraintsImpl.cpp
@@ -434,14 +434,15 @@ static WebMediaConstraints createFromNamedConstraints(ExecutionContext* context,
         return constraints;
     // We ignore unknow names and syntax errors in optional constraints.
     MediaErrorState ignoredErrorState;
-    parseOldStyleNames(context, optional, false, advanced, ignoredErrorState);
-    if (advanced.isEmpty()) {
-        WebVector<WebMediaTrackConstraintSet> emptyVector;
-        constraints.initialize(basic, emptyVector);
-    } else {
-        WebVector<WebMediaTrackConstraintSet> advancedVector(&advanced, 1);
-        constraints.initialize(basic, advancedVector);
-    }
+    Vector<WebMediaTrackConstraintSet> advancedVector;
+    for (const auto& optionalConstraint : optional) {
+        WebMediaTrackConstraintSet advancedElement;
+        WebVector<WebMediaConstraint> elementAsList(&optionalConstraint, 1);
+        parseOldStyleNames(context, elementAsList, false, advancedElement, ignoredErrorState);
+        if (!advancedElement.isEmpty())
+            advancedVector.append(advancedElement);
+    }
+    constraints.initialize(basic, advancedVector);
     return constraints;
 }