Add documentation for platform/bindings

third_party/WebKit/Source/platform/bindings/DOMDataStore.h

 /*
  * Copyright (C) 2009 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 28 matching lines @@
 #include "platform/bindings/WrapperTypeInfo.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/Noncopyable.h"
 #include "platform/wtf/Optional.h"
 #include "platform/wtf/StackUtil.h"
 #include "platform/wtf/StdLibExtras.h"
 #include "v8/include/v8.h"
 
 namespace blink {
 
+// Holds a DOMWrapperMap specialized to map between ScriptWrappable objects and
+// their wrappers and provides an API to perform common operations with this map
+// and manage wrappers in a single world.

[haraken, 2017/04/29 02:39:11]

Clarify that DOMDataStore is a per-world thing and wrappers from different
worlds should not mix.

[adithyas, 2017/05/01 17:41:16]

Done.

 class DOMDataStore {
   WTF_MAKE_NONCOPYABLE(DOMDataStore);
   USING_FAST_MALLOC(DOMDataStore);
 
  public:
   DOMDataStore(v8::Isolate* isolate, bool is_main_world)
       : is_main_world_(is_main_world) {
     // We never use |m_wrapperMap| when it's the main world.
     if (!is_main_world)
       wrapper_map_.emplace(isolate);
@@ skipping 131 matching lines @@
 template <>
 inline void
 DOMWrapperMap<ScriptWrappable>::PersistentValueMapTraits::DisposeWeak(
     const v8::WeakCallbackInfo<WeakCallbackDataType>&) {
   WrapperTypeInfo::WrapperDestroyed();
 }
 
 }  // namespace blink
 
 #endif  // DOMDataStore_h