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

src/runtime/runtime-wasm.cc

 // 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/assembler.h"
 #include "src/compiler/wasm-compiler.h"
 #include "src/conversions.h"
@@ skipping 162 matching lines @@
 }
 
 RUNTIME_FUNCTION(Runtime_ClearThreadInWasm) {
   trap_handler::ClearThreadInWasm();
   return isolate->heap()->undefined_value();
 }
 
 RUNTIME_FUNCTION(Runtime_WasmRunInterpreter) {
   DCHECK_EQ(3, args.length());
   HandleScope scope(isolate);
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, instance_obj, 0);
+  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
   CONVERT_NUMBER_CHECKED(int32_t, func_index, Int32, args[1]);
   CONVERT_ARG_HANDLE_CHECKED(Object, arg_buffer_obj, 2);
-  CHECK(WasmInstanceObject::IsWasmInstanceObject(*instance_obj));
-  Handle<WasmInstanceObject> instance =
-      Handle<WasmInstanceObject>::cast(instance_obj);
 
   // The arg buffer is the raw pointer to the caller's stack. It looks like a
   // Smi (lowest bit not set, as checked by IsSmi), but is no valid Smi. We just
   // cast it back to the raw pointer.
   CHECK(!arg_buffer_obj->IsHeapObject());
   CHECK(arg_buffer_obj->IsSmi());
   uint8_t* arg_buffer = reinterpret_cast<uint8_t*>(*arg_buffer_obj);
 
   // Set the current isolate's context.
   DCHECK_NULL(isolate->context());
@@ skipping 45 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_WasmCompileLazy) {
   DCHECK(args.length() == 0);
   HandleScope scope(isolate);
 
   return *wasm::CompileLazy(isolate);
 }
 
 }  // namespace internal
 }  // namespace v8