[oilpan] Fix iterators over member collections to return Result<T>

Source/wtf/HashTable.h

Index: Source/wtf/HashTable.h
diff --git a/Source/wtf/HashTable.h b/Source/wtf/HashTable.h
index 3a37c64dd9d3672f6cee626aef129ba13f314942..42e818ea27dde11d0fb275575b5dffa08ade3c8c 100644
--- a/Source/wtf/HashTable.h
+++ b/Source/wtf/HashTable.h
@@ -113,7 +113,7 @@ namespace WTF {
         typedef HashTableIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits, Allocator> iterator;
         typedef HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits, Allocator> const_iterator;
         typedef Value ValueType;
-        typedef const ValueType& ReferenceType;
+        typedef typename Traits::IteratorConstGetType GetType;
         typedef const ValueType* PointerType;
         typedef typename Allocator::template IteratorWitness<HashTableType>::Type IteratorWitnessType;
 
@@ -192,13 +192,13 @@ namespace WTF {
         }
 #endif
 
-        PointerType get() const
+        GetType get() const
         {
             checkValidity();
             return m_position;
         }
-        ReferenceType operator*() const { return *get(); }
-        PointerType operator->() const { return get(); }
+        typename Traits::IteratorConstReferenceType operator*() const { return Traits::getToReferenceConstConversion(get()); }
+        GetType operator->() const { return get(); }
 
         const_iterator& operator++()
         {
@@ -274,7 +274,7 @@ namespace WTF {
         typedef HashTableIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits, Allocator> iterator;
         typedef HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits, Allocator> const_iterator;
         typedef Value ValueType;
-        typedef ValueType& ReferenceType;
+        typedef typename Traits::IteratorGetType GetType;
         typedef ValueType* PointerType;
         typedef typename Allocator::template IteratorWitness<HashTableType>::Type IteratorWitnessType;
 
@@ -288,9 +288,9 @@ namespace WTF {
 
         // default copy, assignment and destructor are OK
 
-        PointerType get() const { return const_cast<PointerType>(m_iterator.get()); }
-        ReferenceType operator*() const { return *get(); }
-        PointerType operator->() const { return get(); }
+        GetType get() const { return const_cast<PointerType>(m_iterator.get()); }
+        typename Traits::IteratorReferenceType operator*() const { return Traits::getToReferenceConversion(get()); }
+        GetType operator->() const { return get(); }
 
         iterator& operator++() { ++m_iterator; return *this; }
 
@@ -1430,13 +1430,15 @@ namespace WTF {
 
     // iterator adapters
 
-    template<typename HashTableType, typename ValueType> struct HashTableConstIteratorAdapter {
+    template<typename HashTableType, typename Traits> struct HashTableConstIteratorAdapter {
         HashTableConstIteratorAdapter() {}
         HashTableConstIteratorAdapter(const typename HashTableType::const_iterator& impl) : m_impl(impl) {}
+        typedef typename Traits::IteratorConstGetType GetType;
+        typedef typename HashTableType::ValueTraits::IteratorConstGetType SourceGetType;
 
-        const ValueType* get() const { return (const ValueType*)m_impl.get(); }
-        const ValueType& operator*() const { return *get(); }
-        const ValueType* operator->() const { return get(); }
+        GetType get() const { return (GetType)SourceGetType(m_impl.get()); }
+        typename Traits::IteratorConstReferenceType operator*() const { return Traits::getToReferenceConstConversion(get()); }
+        GetType operator->() const { return get(); }
 
         HashTableConstIteratorAdapter& operator++() { ++m_impl; return *this; }
         // postfix ++ intentionally omitted
@@ -1444,18 +1446,22 @@ namespace WTF {
         typename HashTableType::const_iterator m_impl;
     };
 
-    template<typename HashTableType, typename ValueType> struct HashTableIteratorAdapter {
+    template<typename HashTableType, typename Traits> struct HashTableIteratorAdapter {
+        typedef typename Traits::IteratorGetType GetType;
+        typedef typename HashTableType::ValueTraits::IteratorGetType SourceGetType;
+
         HashTableIteratorAdapter() {}
         HashTableIteratorAdapter(const typename HashTableType::iterator& impl) : m_impl(impl) {}
 
-        ValueType* get() const { return (ValueType*)m_impl.get(); }
-        ValueType& operator*() const { return *get(); }
-        ValueType* operator->() const { return get(); }
+        GetType get() const { return (GetType)SourceGetType(m_impl.get()); }
+        typename Traits::IteratorReferenceType operator*() const { return Traits::getToReferenceConversion(get()); }
+        GetType operator->() const { return get(); }
 
         HashTableIteratorAdapter& operator++() { ++m_impl; return *this; }
         // postfix ++ intentionally omitted
 
-        operator HashTableConstIteratorAdapter<HashTableType, ValueType>() {
+        operator HashTableConstIteratorAdapter<HashTableType, Traits>()
+        {
             typename HashTableType::const_iterator i = m_impl;
             return i;
         }