Worklet: Move Worklet::Initialize() into ThreadedWorklet for cleanup

third_party/WebKit/Source/core/workers/ThreadedWorklet.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 ThreadedWorklet_h
 #define ThreadedWorklet_h
 
 #include "core/workers/Worklet.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
@@ skipping 11 matching lines @@
 // worklets. This and MainThreadWorklet will be merged into the base Worklet
 // class once threaded worklets are also ready to use module loading.
 class CORE_EXPORT ThreadedWorklet : public Worklet,
                                     public WorkletScriptLoader::Client {
   USING_GARBAGE_COLLECTED_MIXIN(ThreadedWorklet);
   WTF_MAKE_NONCOPYABLE(ThreadedWorklet);
 
  public:
   virtual ~ThreadedWorklet() = default;
 
+  // Called when addModule() is called for the first time.
+  virtual void Initialize() = 0;

[kouhei (in TOK), 2017/04/26 10:47:37]

Can we rename Initialize method to more descriptive name?
Suggestion: InitializeBackingThreadAndProxy()

[nhiroki, 2017/04/26 11:01:46]

SG. Let me rename this in a separate CL because it requires wider changes
(including AnimationWorklet, CompositorWorklet and AudioWorklet)

+  virtual bool IsInitialized() const = 0;
+
   // Worklet
   ScriptPromise addModule(ScriptState*, const String& url) final;
 
   // WorkletScriptLoader::Client
   void NotifyWorkletScriptLoadingFinished(WorkletScriptLoader*,
                                           const ScriptSourceCode&) final;
 
   // ContextLifecycleObserver
   void ContextDestroyed(ExecutionContext*) final;
 
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   explicit ThreadedWorklet(LocalFrame*);
 
  private:
   HeapHashMap<Member<WorkletScriptLoader>, Member<ScriptPromiseResolver>>
       loader_to_resolver_map_;
 };
 
 }  // namespace blink
 
 #endif  // ThreadedWorklet_h