Support constructor declarations in analyzer2dart.

pkg/compiler/lib/src/dart_backend/placeholder_collector.dart

Index: pkg/compiler/lib/src/dart_backend/placeholder_collector.dart
diff --git a/pkg/compiler/lib/src/dart_backend/placeholder_collector.dart b/pkg/compiler/lib/src/dart_backend/placeholder_collector.dart
index 694b62379db603a5b0c8af8c90592fb6a26579ea..9f9a2b858b4988dbe588635f28f5eab9c55f5f2a 100644
--- a/pkg/compiler/lib/src/dart_backend/placeholder_collector.dart
+++ b/pkg/compiler/lib/src/dart_backend/placeholder_collector.dart
@@ -189,7 +189,6 @@ class PlaceholderCollector extends Visitor {
       FunctionElement element, FunctionExpression node) {
     if (element.isConstructor) {
       ConstructorElement constructor = element;
-      DartType type = element.enclosingClass.thisType.asRaw();
       tryMakeConstructorPlaceholder(node.name, element);
       RedirectingFactoryBody bodyAsRedirectingFactoryBody =
           node.body.asRedirectingFactoryBody();
@@ -197,7 +196,6 @@ class PlaceholderCollector extends Visitor {
         // Factory redirection.
         FunctionElement redirectTarget = constructor.immediateRedirectionTarget;
         assert(redirectTarget != null && redirectTarget != element);
-        type = redirectTarget.enclosingClass.thisType.asRaw();
         tryMakeConstructorPlaceholder(
             bodyAsRedirectingFactoryBody.constructorReference,
             redirectTarget);