[wasm] Introduce instance types for WebAssembly.* objects.

src/wasm/wasm-interpreter.h

Index: src/wasm/wasm-interpreter.h
diff --git a/src/wasm/wasm-interpreter.h b/src/wasm/wasm-interpreter.h
index 5d608a89496406aefebdc561cfc11932eda107ee..a4a9320c3ab6189180938a8578ef7843c2b9d56d 100644
--- a/src/wasm/wasm-interpreter.h
+++ b/src/wasm/wasm-interpreter.h
@@ -90,7 +90,7 @@ struct WasmVal {
   }
 };
 
-#define DECLARE_CAST(field, localtype, ctype)  \
+#define DECLARE_CASTS(field, localtype, ctype) \
   template <>                                  \
   inline ctype WasmVal::to_unchecked() const { \
     return val.field;                          \
@@ -100,7 +100,7 @@ struct WasmVal {
     CHECK_EQ(localtype, type);                 \
     return val.field;                          \
   }
-FOREACH_UNION_MEMBER(DECLARE_CAST)
+FOREACH_UNION_MEMBER(DECLARE_CASTS)
 #undef DECLARE_CAST
 
 // Representation of frames within the interpreter.