Insert CHECK()s to ensure module-related code are not executed without the flag

third_party/WebKit/Source/bindings/core/v8/ScriptModule.cpp

 // Copyright 2017 The Chromium 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 "bindings/core/v8/ScriptModule.h"
 
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "core/dom/Modulator.h"
 #include "core/dom/ScriptModuleResolver.h"
 
 namespace blink {
 
+ScriptModule::ScriptModule() {
+  // We ensure module-related code is not executed without the flag.
+  // https://crbug.com/715376
+  CHECK(RuntimeEnabledFeatures::moduleScriptsEnabled());
+}
+
+ScriptModule::ScriptModule(WTF::HashTableDeletedValueType)
+    : module_(WTF::kHashTableDeletedValue) {
+  // We ensure module-related code is not executed without the flag.
+  // https://crbug.com/715376
+  CHECK(RuntimeEnabledFeatures::moduleScriptsEnabled());
+}
+
 ScriptModule::ScriptModule(v8::Isolate* isolate, v8::Local<v8::Module> module)
     : module_(SharedPersistent<v8::Module>::Create(module, isolate)),
       identity_hash_(static_cast<unsigned>(module->GetIdentityHash())) {
+  // We ensure module-related code is not executed without the flag.
+  // https://crbug.com/715376
+  CHECK(RuntimeEnabledFeatures::moduleScriptsEnabled());
+
   DCHECK(!module_->IsEmpty());
 }
 
 ScriptModule::~ScriptModule() {}
 
 ScriptModule ScriptModule::Compile(v8::Isolate* isolate,
                                    const String& source,
                                    const String& file_name,
                                    AccessControlStatus access_control_status) {
+  // We ensure module-related code is not executed without the flag.
+  // https://crbug.com/715376
+  CHECK(RuntimeEnabledFeatures::moduleScriptsEnabled());
+
   v8::TryCatch try_catch(isolate);
   try_catch.SetVerbose(true);
   v8::Local<v8::Module> module;
   if (!V8ScriptRunner::CompileModule(isolate, source, file_name,
                                      access_control_status)
            .ToLocal(&module)) {
     // Compilation error is not used in Blink implementaion logic.
     // Note: Error message is delivered to user (e.g. console) by message
     // listeners set on v8::Isolate. See V8Initializer::initalizeMainThread().
     // TODO(nhiroki): Revisit this when supporting modules on worker threads.
@@ skipping 36 matching lines @@
   if (!V8ScriptRunner::EvaluateModule(module_->NewLocal(isolate),
                                       script_state->GetContext(), isolate)
            .ToLocal(&result)) {
     return;
   }
 }
 
 void ScriptModule::ReportException(ScriptState* script_state,
                                    v8::Local<v8::Value> exception,
                                    const String& file_name) {
+  // We ensure module-related code is not executed without the flag.
+  // https://crbug.com/715376
+  CHECK(RuntimeEnabledFeatures::moduleScriptsEnabled());
+
   v8::Isolate* isolate = script_state->GetIsolate();
 
   v8::TryCatch try_catch(isolate);
   try_catch.SetVerbose(true);
 
   V8ScriptRunner::ReportExceptionForModule(isolate, exception, file_name);
 }
 
 Vector<String> ScriptModule::ModuleRequests(ScriptState* script_state) {
   if (IsNull())
     return Vector<String>();
 
   v8::Local<v8::Module> module = module_->NewLocal(script_state->GetIsolate());
 
   Vector<String> ret;
 
   int length = module->GetModuleRequestsLength();
   ret.ReserveInitialCapacity(length);
   for (int i = 0; i < length; ++i) {
     v8::Local<v8::String> v8_name = module->GetModuleRequest(i);
     ret.push_back(ToCoreString(v8_name));
   }
   return ret;
 }
 
 v8::MaybeLocal<v8::Module> ScriptModule::ResolveModuleCallback(
     v8::Local<v8::Context> context,
     v8::Local<v8::String> specifier,
     v8::Local<v8::Module> referrer) {
+  // We ensure module-related code is not executed without the flag.
+  // https://crbug.com/715376
+  CHECK(RuntimeEnabledFeatures::moduleScriptsEnabled());
+
   v8::Isolate* isolate = context->GetIsolate();
   Modulator* modulator = Modulator::From(ScriptState::From(context));
   DCHECK(modulator);
 
   ScriptModule referrer_record(isolate, referrer);
   ExceptionState exception_state(isolate, ExceptionState::kExecutionContext,
                                  "ScriptModule", "resolveModuleCallback");
   ScriptModule resolved = modulator->GetScriptModuleResolver()->Resolve(
       ToCoreStringWithNullCheck(specifier), referrer_record, exception_state);
   if (resolved.IsNull()) {
     DCHECK(exception_state.HadException());
     return v8::MaybeLocal<v8::Module>();
   }
 
   DCHECK(!exception_state.HadException());
   return v8::MaybeLocal<v8::Module>(resolved.module_->NewLocal(isolate));
 }
 
 }  // namespace blink