binding: Moves hasPendingActivity from ActiveScriptWrappable to ScriptWrappable.

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

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 22 matching lines @@
 
 #include "bindings/core/v8/WrapperTypeInfo.h"
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/TypeTraits.h"
 #include <v8.h>
 
 namespace blink {
 
-/**
- * ScriptWrappable wraps a V8 object and its WrapperTypeInfo.
- *
- * ScriptWrappable acts much like a v8::Persistent<> in that it keeps a
- * V8 object alive.
- *
- *  The state transitions are:
- *  - new: an empty ScriptWrappable.
- *  - setWrapper: install a v8::Persistent (or empty)
- *  - disposeWrapper (via setWeakCallback, triggered by V8 garbage collecter):
- *        remove v8::Persistent and become empty.
- */
+// ScriptWrappable wraps a V8 object and its WrapperTypeInfo.
+//
+// ScriptWrappable acts much like a v8::Persistent<> in that it keeps a
+// V8 object alive.

[haraken, 2016/08/23 07:55:40]

This is not really correct. ScriptWrappable keeps a weak v8::Persistent to the
DOM wrapper. It doesn't keep the DOM wrapper alive.

[Yuki, 2016/08/23 09:49:52]

I've rewritten the class comment.

 class CORE_EXPORT ScriptWrappable {
     WTF_MAKE_NONCOPYABLE(ScriptWrappable);
 public:
     ScriptWrappable() { }
 
     template<typename T>
     T* toImpl()
     {
         // All ScriptWrappables are managed by the Blink GC heap; check that
         // |T| is a garbage collected type.
@@ skipping 18 matching lines @@
 
     // Creates and returns a new wrapper object.
     virtual v8::Local<v8::Object> wrap(v8::Isolate*, v8::Local<v8::Object> creationContext);
 
     // Associates the instance with the given |wrapper| if this instance is not
     // yet associated with any wrapper.  Returns the wrapper already associated
     // or |wrapper| if not yet associated.
     // The caller should always use the returned value rather than |wrapper|.
     virtual v8::Local<v8::Object> associateWithWrapper(v8::Isolate*, const WrapperTypeInfo*, v8::Local<v8::Object> wrapper) WARN_UNUSED_RETURN;
 
+    virtual bool hasPendingActivity() const { return false; }

[haraken, 2016/08/23 07:55:40]

Add a comment.

+
     // Associates this instance with the given |wrapper| if this instance is not
     // yet associated with any wrapper.  Returns true if the given wrapper is
     // associated with this instance, or false if this instance is already
     // associated with a wrapper.  In the latter case, |wrapper| will be updated
     // to the existing wrapper.
     bool setWrapper(v8::Isolate* isolate, const WrapperTypeInfo* wrapperTypeInfo, v8::Local<v8::Object>& wrapper) WARN_UNUSED_RETURN
     {
         ASSERT(!wrapper.IsEmpty());
         if (UNLIKELY(containsWrapper())) {
             wrapper = mainWorldWrapper(isolate);
@@ skipping 34 matching lines @@
         return containsWrapper();
     }
 
     void setReference(const v8::Persistent<v8::Object>& parent, v8::Isolate* isolate)
     {
         isolate->SetReference(parent, m_mainWorldWrapper);
     }
 
     bool containsWrapper() const { return !m_mainWorldWrapper.IsEmpty(); }
 
-    /**
-     *  Mark wrapper of this ScriptWrappable as alive in V8. Only marks
-     *  wrapper in the main world. To mark wrappers in all worlds call
-     *  ScriptWrappableVisitor::markWrapper(ScriptWrappable*, v8::Isolate*)
-     */
+    //  Mark wrapper of this ScriptWrappable as alive in V8. Only marks
+    //  wrapper in the main world. To mark wrappers in all worlds call
+    //  ScriptWrappableVisitor::markWrapper(ScriptWrappable*, v8::Isolate*)
     void markWrapper(const WrapperVisitor*) const;
 
     DECLARE_VIRTUAL_TRACE_WRAPPERS() {};
 
-    // With Oilpan we don't need a ScriptWrappable destructor.
-    //
-    // 'RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(!containsWrapper())' is not needed
-    // because Oilpan is not using reference counting at all. If containsWrapper() is true,
-    // it means that ScriptWrappable still has a wrapper. In this case, the destructor
-    // must not be called since the wrapper has a persistent handle back to this ScriptWrappable object.
-    // Assuming that Oilpan's GC is correct (If we cannot assume this, a lot of more things are
-    // already broken), we must not hit the RELEASE_ASSERT.
-
 private:
     // These classes are exceptionally allowed to use mainWorldWrapper().
     friend class DOMDataStore;
     friend class V8HiddenValue;
     friend class V8PrivateProperty;
     friend class WebGLRenderingContextBase;
 
     v8::Local<v8::Object> mainWorldWrapper(v8::Isolate* isolate) const
     {
         return v8::Local<v8::Object>::New(isolate, m_mainWorldWrapper);
@@ skipping 30 matching lines @@
 // in X's cpp code, and instantiate X, i.e. "template class X;".
 #define DECLARE_WRAPPERTYPEINFO() \
 public: \
     const WrapperTypeInfo* wrapperTypeInfo() const override; \
 private: \
     typedef void end_of_define_wrappertypeinfo_not_reached_t
 
 } // namespace blink
 
 #endif // ScriptWrappable_h