Create bare-bones ScriptModule class

Provides a ScriptModule wrapper around v8::Module, as
well as primordial forms of the three basic operations
on modules:

  - compile(), a static method which takes a string and
    returns a ScriptModule
  - instantiate(), which "links" a module with its dependencies
    (the initial implementation does no actual linking)
  - evaluate(), which runs the module (and its dependencies;
    naturally this version doesn't do the latter)

Landing this in its early state makes it easier for others
working on <script type="module"> support to make progress
on other CLs, many of which will interact with this class

BUG=594639

Review-Url: https://codereview.chromium.org/2566513002
Cr-Commit-Position: refs/heads/master@{#443112}

third_party/WebKit/Source/bindings/bindings.gni

@@ -92,6 +92,8 @@ bindings_core_v8_files =
                     "core/v8/ScriptEventListener.h",
                     "core/v8/ScriptFunction.cpp",
                     "core/v8/ScriptFunction.h",
+                    "core/v8/ScriptModule.cpp",
+                    "core/v8/ScriptModule.h",
                     "core/v8/ScriptPromise.cpp",
                     "core/v8/ScriptPromise.h",
                     "core/v8/ScriptPromiseProperties.h",

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/V8Binding.h"
+
+namespace blink {
+
+ScriptModule::ScriptModule(v8::Isolate* isolate, v8::Local<v8::Module> module)
+    : m_module(SharedPersistent<v8::Module>::create(module, isolate)) {}
+
+ScriptModule::~ScriptModule() {}
+
+ScriptModule ScriptModule::compile(v8::Isolate* isolate,
+                                   const String& source,
+                                   const String& fileName) {
+  v8::TryCatch tryCatch(isolate);
+  tryCatch.SetVerbose(true);
+  v8::Local<v8::Module> module;
+  if (!v8Call(V8ScriptRunner::compileModule(isolate, source, fileName), module,
+              tryCatch)) {
+    // TODO(adamk): Signal failure somehow.
+    return ScriptModule(isolate, module);
+  }
+  return ScriptModule(isolate, module);
+}
+
+v8::MaybeLocal<v8::Module> dummyCallback(v8::Local<v8::Context> context,
+                                         v8::Local<v8::String> specifier,
+                                         v8::Local<v8::Module> referrer) {
+  return v8::MaybeLocal<v8::Module>();
+}
+
+bool ScriptModule::instantiate(ScriptState* scriptState) {
+  DCHECK(!isNull());
+  v8::Local<v8::Context> context = scriptState->context();
+  // TODO(adamk): pass in a real callback.
+  return m_module->newLocal(scriptState->isolate())
+      ->Instantiate(context, &dummyCallback);
+}
+
+void ScriptModule::evaluate(ScriptState* scriptState) {
+  v8::Isolate* isolate = scriptState->isolate();
+  v8::TryCatch tryCatch(isolate);
+  tryCatch.SetVerbose(true);
+  v8::Local<v8::Value> result;
+  if (!v8Call(V8ScriptRunner::evaluateModule(m_module->newLocal(isolate),
+                                             scriptState->context(), isolate),
+              result, tryCatch)) {
+    // TODO(adamk): report error
+  }
+}
+
+}  // namespace blink

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

+// 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.
+
+#ifndef ScriptModule_h
+#define ScriptModule_h
+
+#include "bindings/core/v8/ScriptState.h"
+#include "bindings/core/v8/SharedPersistent.h"
+#include "core/CoreExport.h"
+#include "wtf/Allocator.h"
+#include "wtf/text/WTFString.h"
+#include <v8.h>
+
+namespace blink {
+
+class CORE_EXPORT ScriptModule final {
+  DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
+
+ public:
+  static ScriptModule compile(v8::Isolate*,
+                              const String& source,
+                              const String& fileName);
+
+  ScriptModule(const ScriptModule& module) : m_module(module.m_module) {}
+  ~ScriptModule();
+
+  bool instantiate(ScriptState*);
+  void evaluate(ScriptState*);
+
+  bool isNull() const { return m_module->isEmpty(); }
+
+ private:
+  ScriptModule(v8::Isolate*, v8::Local<v8::Module>);
+
+  RefPtr<SharedPersistent<v8::Module>> m_module;
+};
+
+}  // namespace blink
+
+#endif  // ScriptModule_h

third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp

@@ -493,6 +493,18 @@ v8::MaybeLocal<v8::Script> V8ScriptRunner::compileScript(
   return (*compileFn)(isolate, code, origin);
 }
 
+v8::MaybeLocal<v8::Module> V8ScriptRunner::compileModule(
+    v8::Isolate* isolate,
+    const String& source,
+    const String& fileName) {
+  TRACE_EVENT1("v8", "v8.compileModule", "fileName", fileName.utf8());
+  // TODO(adamk): Add Inspector integration?
+  // TODO(adamk): Pass more info into ScriptOrigin.
+  v8::ScriptOrigin origin(v8String(isolate, fileName));
+  v8::ScriptCompiler::Source scriptSource(v8String(isolate, source), origin);
+  return v8::ScriptCompiler::CompileModule(isolate, &scriptSource);
+}
+
 v8::MaybeLocal<v8::Value> V8ScriptRunner::runCompiledScript(
     v8::Isolate* isolate,
     v8::Local<v8::Script> script,
@@ -660,6 +672,16 @@ v8::MaybeLocal<v8::Value> V8ScriptRunner::callInternalFunction(
   return result;
 }
 
+v8::MaybeLocal<v8::Value> V8ScriptRunner::evaluateModule(
+    v8::Local<v8::Module> module,
+    v8::Local<v8::Context> context,
+    v8::Isolate* isolate) {
+  TRACE_EVENT0("v8", "v8.evaluateModule");
+  v8::MicrotasksScope microtasksScope(isolate,
+                                      v8::MicrotasksScope::kRunMicrotasks);
+  return module->Evaluate(context);
+}
+
 v8::MaybeLocal<v8::Object> V8ScriptRunner::instantiateObject(
     v8::Isolate* isolate,
     v8::Local<v8::ObjectTemplate> objectTemplate) {

third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.h

@@ -81,6 +81,9 @@ class CORE_EXPORT V8ScriptRunner final {
       CachedMetadataHandler* = nullptr,
       AccessControlStatus = SharableCrossOrigin,
       V8CacheOptions = V8CacheOptionsDefault);
+  static v8::MaybeLocal<v8::Module> compileModule(v8::Isolate*,
+                                                  const String& source,
+                                                  const String& fileName);
   static v8::MaybeLocal<v8::Value> runCompiledScript(v8::Isolate*,
                                                      v8::Local<v8::Script>,
                                                      ExecutionContext*);
@@ -110,6 +113,9 @@ class CORE_EXPORT V8ScriptRunner final {
                                                 int argc,
                                                 v8::Local<v8::Value> info[],
                                                 v8::Isolate*);
+  static v8::MaybeLocal<v8::Value> evaluateModule(v8::Local<v8::Module>,
+                                                  v8::Local<v8::Context>,
+                                                  v8::Isolate*);
   static v8::MaybeLocal<v8::Object> instantiateObject(
       v8::Isolate*,
       v8::Local<v8::ObjectTemplate>);