[wasm] Remove MicrotasksScope usage from wasm-js.cc

All of the places where MicrotasksScope is placed on the
stack are callbacks from JavaScript, so microtasks would
never run microtasks inside one of these methods.

Change-Id: I6dc36971189d6479138b58b90e3b9acae0c3ef73
Reviewed-on: https://chromium-review.googlesource.com/c/1277721Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56687}

src/wasm/wasm-js.cc

@@ -417,7 +417,6 @@ class AsyncInstantiateCompileResultResolver
 void WebAssemblyCompile(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  MicrotasksScope runs_microtasks(isolate, MicrotasksScope::kRunMicrotasks);
 
   HandleScope scope(isolate);
   ScheduledErrorThrower thrower(i_isolate, "WebAssembly.compile()");
@@ -452,7 +451,6 @@ void WebAssemblyCompileStreaming(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  MicrotasksScope runs_microtasks(isolate, MicrotasksScope::kRunMicrotasks);
   HandleScope scope(isolate);
   ScheduledErrorThrower thrower(i_isolate, "WebAssembly.compile()");
   Local<Context> context = isolate->GetCurrentContext();
@@ -671,8 +669,6 @@ void WebAssemblyInstance(const v8::FunctionCallbackInfo<v8::Value>& args) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   i_isolate->CountUsage(
       v8::Isolate::UseCounterFeature::kWebAssemblyInstantiation);
-  MicrotasksScope does_not_run_microtasks(isolate,
-                                          MicrotasksScope::kDoNotRunMicrotasks);
 
   HandleScope scope(args.GetIsolate());
   if (i_isolate->wasm_instance_callback()(args)) return;
@@ -703,7 +699,6 @@ void WebAssemblyInstantiateStreaming(
   i_isolate->CountUsage(
       v8::Isolate::UseCounterFeature::kWebAssemblyInstantiation);
 
-  MicrotasksScope runs_microtasks(isolate, MicrotasksScope::kRunMicrotasks);
   HandleScope scope(isolate);
   Local<Context> context = isolate->GetCurrentContext();
   ScheduledErrorThrower thrower(i_isolate,
@@ -782,7 +777,6 @@ void WebAssemblyInstantiate(const v8::FunctionCallbackInfo<v8::Value>& args) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   i_isolate->CountUsage(
       v8::Isolate::UseCounterFeature::kWebAssemblyInstantiation);
-  MicrotasksScope runs_microtasks(isolate, MicrotasksScope::kRunMicrotasks);
 
   ScheduledErrorThrower thrower(i_isolate, "WebAssembly Instantiation");