Change List constructors.

sdk/lib/_internal/compiler/implementation/ssa/optimize.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart b/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
index e27f697219c86f8b502a192a324313fd6a712c9c..c01e4714e43908ff10567f1d3cb3d473e37a2869 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
@@ -256,11 +256,17 @@ class SsaConstantFolder extends HBaseVisitor implements OptimizationPhase {
     DartType defaultClass = compiler.listClass.defaultClass;
     // TODO(ngeoffray): make sure that the only reason the List class is
     // not resolved is because it's not being used.
-    return element.isConstructor()
-        && defaultClass != null
-        && element.enclosingElement.declaration == defaultClass.element
-        && node.inputs.length == 2
-        && node.inputs[1].isInteger(types);
+    if (defaultClass == null) return false;
+    if (!element.isConstructor()) return false;
+    // TODO(ngeoffray): cache constructor.
+    if (element.enclosingElement.declaration != defaultClass.element) {
+      return false;
+    }
+    FunctionElement fixedLengthListConstructor =
+        compiler.listClass.lookupConstructor(
+            new Selector.callConstructor(const SourceString("fixedLength"),
+                                         compiler.listClass.getLibrary()));
+    return element == fixedLengthListConstructor.defaultImplementation;
   }
 
   HInstruction visitInvokeStatic(HInvokeStatic node) {