new classes: implement default constructors.

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index bb9a417867e927a9c247b33eefc520ddb9655979..0edd643796e0d6bd5d3c0324e24fa7745a998c9a 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -823,7 +823,9 @@ enum FunctionKind {
   kAccessorFunction = 1 << 3,
   kDefaultConstructor = 1 << 4,
   kSubclassConstructor = 1 << 5,
-  kBaseConstructor = 1 << 6
+  kBaseConstructor = 1 << 6,
+  kDefaultBaseConstructor = kDefaultConstructor | kBaseConstructor,
+  kDefaultSubclassConstructor = kDefaultConstructor | kSubclassConstructor,
 };
 
 
@@ -834,7 +836,8 @@ inline bool IsValidFunctionKind(FunctionKind kind) {
          kind == FunctionKind::kConciseMethod ||
          kind == FunctionKind::kConciseGeneratorMethod ||
          kind == FunctionKind::kAccessorFunction ||
-         kind == FunctionKind::kDefaultConstructor ||
+         kind == FunctionKind::kDefaultBaseConstructor ||
+         kind == FunctionKind::kDefaultSubclassConstructor ||
          kind == FunctionKind::kBaseConstructor ||
          kind == FunctionKind::kSubclassConstructor;
 }