Introduce ModulePendingScript

third_party/WebKit/Source/core/dom/ModulePendingScript.h

Index: third_party/WebKit/Source/core/dom/ModulePendingScript.h
diff --git a/third_party/WebKit/Source/core/dom/ModulePendingScript.h b/third_party/WebKit/Source/core/dom/ModulePendingScript.h
new file mode 100644
index 0000000000000000000000000000000000000000..62ecccbbcfbac8682a2bb6da632754e4810ed829
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/ModulePendingScript.h
@@ -0,0 +1,98 @@
+// 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 ModulePendingScript_h
+#define ModulePendingScript_h
+
+#include "core/dom/Modulator.h"
+#include "core/dom/ModuleScript.h"
+#include "core/dom/PendingScript.h"
+
+namespace blink {
+
+class ModulePendingScript;
+
+// ModulePendingScriptTreeClient is used to connect from Modulator::FetchTree()
+// to ModulePendingScript. Because ModulePendingScript is created after
+// Modulator::FetchTree() is called, ModulePendingScriptTreeClient is
+// registered as ModuleTreeClient to FetchTree() first, and later
+// ModulePendingScript is supplied to ModulePendingScriptTreeClient via
+// SetPendingScript() and is notified of module tree load finish.
+class ModulePendingScriptTreeClient final
+    : public GarbageCollectedFinalized<ModulePendingScriptTreeClient>,
+      public ModuleTreeClient {
+  USING_GARBAGE_COLLECTED_MIXIN(ModulePendingScriptTreeClient);
+
+ public:
+  static ModulePendingScriptTreeClient* Create() {
+    return new ModulePendingScriptTreeClient();
+  }
+  virtual ~ModulePendingScriptTreeClient() = default;
+
+  void SetPendingScript(ModulePendingScript* client);
+
+  ModuleScript* GetModuleScript() const { return module_script_; }
+
+  DECLARE_TRACE();
+
+ private:
+  ModulePendingScriptTreeClient();
+
+  // Implements ModuleTreeClient
+  void NotifyModuleTreeLoadFinished(ModuleScript*) override;
+
+  bool finished_ = false;
+  Member<ModuleScript> module_script_;
+  Member<ModulePendingScript> pending_script_;
+};
+
+// PendingScript for a module script
+// https://html.spec.whatwg.org/#module-script.
+class CORE_EXPORT ModulePendingScript : public PendingScript {
+ public:
+  static ModulePendingScript* Create(ScriptElementBase* element,
+                                     ModulePendingScriptTreeClient* client) {
+    return new ModulePendingScript(element, client);
+  }
+
+  ~ModulePendingScript() override;
+
+  void NotifyModuleTreeLoadFinished();
+
+  ModuleScript* GetModuleScript() const {
+    return module_tree_client_->GetModuleScript();
+  }
+
+  DECLARE_TRACE();
+
+ private:
+  ModulePendingScript(ScriptElementBase*, ModulePendingScriptTreeClient*);
+
+  // PendingScript
+  ScriptType GetScriptType() const override { return ScriptType::kModule; }
+  Script* GetSource(const KURL& document_url,
+                    bool& error_occurred) const override;
+  bool IsReady() const override { return ready_; }
+  bool IsExternal() const override { return true; }
+  bool ErrorOccurred() const override;
+  bool WasCanceled() const override { return false; }
+
+  void StartStreamingIfPossible(Document*, ScriptStreamer::Type) override {}
+  KURL UrlForClassicScript() const override {
+    NOTREACHED();
+    return KURL();
+  }
+  void RemoveFromMemoryCache() override { NOTREACHED(); }

[kouhei (in TOK), 2017/04/14 00:20:45]

Comment explaining "why" would help

+
+  void DisposeInternal() override;
+
+  void CheckState() const override {}
+
+  Member<ModulePendingScriptTreeClient> module_tree_client_;
+  bool ready_ = false;
+};
+
+}  // namespace blink
+
+#endif  // ModulePendingScript_h