[wasm] Make {JSPromise::Resolve} and friend MUST_USE_RESULT.

R=adamk@chromium.org

Change-Id: Ib6b66003aaf8694c1e5eed6db7d2537322eddad8
Reviewed-on: https://chromium-review.googlesource.com/897498Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51051}

src/objects.h

@@ -4033,10 +4033,10 @@ class JSPromise : public JSObject {
   v8::Promise::PromiseState status() const;
 
   // Resolve/reject the promise with a given value.
-  static MaybeHandle<Object> Resolve(Handle<JSPromise> promise,
-                                     Handle<Object> value);
-  static MaybeHandle<Object> Reject(Handle<JSPromise> promise,
-                                    Handle<Object> value);
+  MUST_USE_RESULT static MaybeHandle<Object> Resolve(Handle<JSPromise> promise,
+                                                     Handle<Object> value);
+  MUST_USE_RESULT static MaybeHandle<Object> Reject(Handle<JSPromise> promise,
+                                                    Handle<Object> value);
 
   DECL_CAST(JSPromise)
 

src/wasm/module-compiler.cc

@@ -3459,14 +3459,18 @@ void AsyncCompileJob::AsyncCompileFailed(ErrorThrower& thrower) {
   // {job} keeps the {this} pointer alive.
   std::shared_ptr<AsyncCompileJob> job =
       isolate_->wasm_engine()->compilation_manager()->RemoveJob(this);
-  JSPromise::Reject(module_promise_, thrower.Reify());
+  MaybeHandle<Object> promise_result =
+      JSPromise::Reject(module_promise_, thrower.Reify());
+  CHECK_EQ(promise_result.is_null(), isolate_->has_pending_exception());
 }
 
 void AsyncCompileJob::AsyncCompileSucceeded(Handle<Object> result) {
   // {job} keeps the {this} pointer alive.
   std::shared_ptr<AsyncCompileJob> job =
       isolate_->wasm_engine()->compilation_manager()->RemoveJob(this);
-  JSPromise::Resolve(module_promise_, result);
+  MaybeHandle<Object> promise_result =
+      JSPromise::Resolve(module_promise_, result);
+  CHECK_EQ(promise_result.is_null(), isolate_->has_pending_exception());
 }
 
 // A closure to run a compilation step (either as foreground or background

src/wasm/wasm-engine.cc

@@ -63,10 +63,13 @@ void WasmEngine::AsyncInstantiate(Isolate* isolate, Handle<JSPromise> promise,
   MaybeHandle<WasmInstanceObject> instance_object = SyncInstantiate(
       isolate, &thrower, module_object, imports, Handle<JSArrayBuffer>::null());
   if (thrower.error()) {
-    JSPromise::Reject(promise, thrower.Reify());
+    MaybeHandle<Object> result = JSPromise::Reject(promise, thrower.Reify());
+    CHECK_EQ(result.is_null(), isolate->has_pending_exception());
     return;
   }
-  JSPromise::Resolve(promise, instance_object.ToHandleChecked());
+  Handle<WasmInstanceObject> instance = instance_object.ToHandleChecked();
+  MaybeHandle<Object> result = JSPromise::Resolve(promise, instance);
+  CHECK_EQ(result.is_null(), isolate->has_pending_exception());
 }
 
 void WasmEngine::AsyncCompile(Isolate* isolate, Handle<JSPromise> promise,
@@ -87,11 +90,13 @@ void WasmEngine::AsyncCompile(Isolate* isolate, Handle<JSPromise> promise,
       module_object = SyncCompile(isolate, &thrower, bytes);
     }
     if (thrower.error()) {
-      JSPromise::Reject(promise, thrower.Reify());
+      MaybeHandle<Object> result = JSPromise::Reject(promise, thrower.Reify());
+      CHECK_EQ(result.is_null(), isolate->has_pending_exception());
       return;
     }
     Handle<WasmModuleObject> module = module_object.ToHandleChecked();
-    JSPromise::Resolve(promise, module);
+    MaybeHandle<Object> result = JSPromise::Resolve(promise, module);
+    CHECK_EQ(result.is_null(), isolate->has_pending_exception());
     return;
   }