Rename and improve "traceable" templates.

third_party/WebKit/Source/wtf/TypeTraits.h

  /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009, 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 230 matching lines @@
 
 namespace blink {
 
 class Visitor;
 
 } // namespace blink
 
 namespace WTF {
 
 template <typename T>
-class NeedsTracing {
+class IsTraceable {
     typedef char YesType;
     typedef struct NoType {
         char padding[8];
     } NoType;
 
     // Note that this also checks if a superclass of V has a trace method.
     template <typename V> static YesType checkHasTraceMethod(V* v, blink::Visitor* p = nullptr, typename std::enable_if<std::is_same<decltype(v->trace(p)), void>::value>::type* g = nullptr);
     template <typename V> static NoType checkHasTraceMethod(...);
 public:
     // We add sizeof(T) to both sides here, because we want it to fail for
     // incomplete types. Otherwise it just assumes that incomplete types do not
     // have a trace method, which may not be true.
     static const bool value = sizeof(YesType) + sizeof(T) == sizeof(checkHasTraceMethod<T>(nullptr)) + sizeof(T);
 };
 
-// Convenience template wrapping the NeedsTracingLazily template in
+// Convenience template wrapping the IsTraceableInCollection template in
 // Collection Traits. It helps make the code more readable.
 template <typename Traits>
-class NeedsTracingTrait {
+class IsTraceableInCollectionTrait {
 public:
-    static const bool value = Traits::template NeedsTracingLazily<>::value;
+    static const bool value = Traits::template IsTraceableInCollection<>::value;
 };
 
 template <typename T, typename U>
-struct NeedsTracing<std::pair<T, U>> {
-    static const bool value = NeedsTracing<T>::value || NeedsTracing<U>::value || IsWeak<T>::value || IsWeak<U>::value;
+struct IsTraceable<std::pair<T, U>> {
+    static const bool value = IsTraceable<T>::value || IsTraceable<U>::value;
 };
 
 // This is used to check that DISALLOW_NEW_EXCEPT_PLACEMENT_NEW objects are not
 // stored in off-heap Vectors, HashTables etc.
 template <typename T>
 struct AllowsOnlyPlacementNew {
 private:
     using YesType = char;
     struct NoType {
         char padding[8];
@@ skipping 64 matching lines @@
 class IsPointerToGarbageCollectedType<T*, false> {
 public:
     static const bool value = IsGarbageCollectedType<T>::value;
 };
 
 } // namespace WTF
 
 using WTF::IsGarbageCollectedType;
 
 #endif // TypeTraits_h