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

Source/wtf/HashTraits.h

Index: Source/wtf/HashTraits.h
diff --git a/Source/wtf/HashTraits.h b/Source/wtf/HashTraits.h
index 433b358cd62dc7e4ea571b4c15905907107c1ceb..2395ff8cf5e34480029a4d35a5f958bb2d41be4c 100644
--- a/Source/wtf/HashTraits.h
+++ b/Source/wtf/HashTraits.h
@@ -75,6 +75,12 @@ namespace WTF {
 
         // Type for functions that do not take ownership, such as contains.
         typedef const T& PeekInType;
+        typedef T* IteratorGetType;
+        typedef const T* IteratorConstGetType;
+        typedef T& IteratorReferenceType;
+        typedef const T& IteratorConstReferenceType;
+        static IteratorReferenceType getToReferenceConversion(IteratorGetType x) { return *x; }
+        static IteratorConstReferenceType getToReferenceConstConversion(IteratorConstGetType x) { return *x; }
         // Type for functions that take ownership, such as add.
         // The store function either not be called or called once to store something passed in.
         // The value passed to the store function will be PassInType.
@@ -132,6 +138,12 @@ namespace WTF {
         static EmptyValueType emptyValue() { return nullptr; }
 
         typedef const OwnPtr<P>& PeekInType;
+        typedef P* IteratorGetType;
+        typedef const P* IteratorConstGetType;
+        typedef P& IteratorReferenceType;
+        typedef const P& IteratorConstReferenceType;
+        static IteratorReferenceType getToReferenceConversion(IteratorGetType x) { return *x; }
+        static IteratorConstReferenceType getToReferenceConstConversion(IteratorConstGetType x) { return *x; }
         typedef PassOwnPtr<P> PassInType;
         static void store(PassOwnPtr<P> value, OwnPtr<P>& storage) { storage = value; }
 
@@ -146,6 +158,12 @@ namespace WTF {
 
     template<typename P> struct HashTraits<RefPtr<P> > : SimpleClassHashTraits<RefPtr<P> > {
         typedef const RefPtr<P>& PeekInType;
+        typedef RefPtr<P>* IteratorGetType;
+        typedef const RefPtr<P>* IteratorConstGetType;
+        typedef RefPtr<P>& IteratorReferenceType;
+        typedef const RefPtr<P>& IteratorConstReferenceType;
+        static IteratorReferenceType getToReferenceConversion(IteratorGetType x) { return *x; }
+        static IteratorConstReferenceType getToReferenceConstConversion(IteratorConstGetType x) { return *x; }
         typedef PassRefPtr<P> PassInType;
         static void store(PassRefPtr<P> value, RefPtr<P>& storage) { storage = value; }