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

src/wasm/wasm-interpreter.h

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_WASM_INTERPRETER_H_
 #define V8_WASM_INTERPRETER_H_
 
 #include "src/wasm/wasm-opcodes.h"
 #include "src/zone/zone-containers.h"
 
@@ skipping 72 matching lines @@
   inline T to() const {
     UNREACHABLE();
   }
 
   template <typename T>
   inline T to_unchecked() const {
     UNREACHABLE();
   }
 };
 
-#define DECLARE_CAST(field, localtype, ctype)  \
+#define DECLARE_CASTS(field, localtype, ctype) \
   template <>                                  \
   inline ctype WasmVal::to_unchecked() const { \
     return val.field;                          \
   }                                            \
   template <>                                  \
   inline ctype WasmVal::to() const {           \
     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.
 //
 // Layout of a frame:
 // -----------------
 // stack slot #N  ‾\.
 // ...             |  stack entries: GetStackHeight(); GetStackValue()
 // stack slot #0  _/·
 // local #L       ‾\.
@@ skipping 162 matching lines @@
  private:
   Zone zone_;
   WasmInterpreterInternals* internals_;
 };
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_INTERPRETER_H_