Remove C::swap(C*) where C = Hash{Map,Set}<T>.

third_party/WebKit/Source/platform/heap/HeapAllocator.h

Index: third_party/WebKit/Source/platform/heap/HeapAllocator.h
diff --git a/third_party/WebKit/Source/platform/heap/HeapAllocator.h b/third_party/WebKit/Source/platform/heap/HeapAllocator.h
index 31441f1f08e99b1af055122b42ff52ce607fb0b2..97e0bca3e5c06f70b6fb5e72a385a440292ce1b9 100644
--- a/third_party/WebKit/Source/platform/heap/HeapAllocator.h
+++ b/third_party/WebKit/Source/platform/heap/HeapAllocator.h
@@ -150,22 +150,6 @@ public:
     }
 #endif
 
-    template<typename T>
-    struct ResultType {
-        using Type = T*;
-    };
-
-    template<typename T>
-    struct OtherType {
-        using Type = T*;
-    };
-
-    template<typename T>
-    static T& getOther(T* other)
-    {
-        return *other;
-    }
-
     static void enterGCForbiddenScope()
     {
         ThreadState::current()->enterGCForbiddenScope();