Remove dead function HashMap::Insert

It wouldn't compile anyway, because AddPassingHashCode doesn't exist

Change-Id: I1e2b282dd1d62033b34fe769799b8c81fa9ede37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2143873Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Bartek Nowierski <bartekn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757823}

third_party/blink/renderer/platform/wtf/hash_map.h

@@ -193,18 +193,6 @@ class HashMap {
   template <typename HashTranslator, typename T>
   bool Contains(const T&) const;
 
-  // An alternate version of insert() that finds the object by hashing and
-  // comparing with some other type, to avoid the cost of type conversion if
-  // the object is already in the table. HashTranslator must have the
-  // following function members:
-  //   static unsigned hash(const T&);
-  //   static bool equal(const ValueType&, const T&);
-  //   static translate(ValueType&, const T&, unsigned hashCode);
-  template <typename HashTranslator,
-            typename IncomingKeyType,
-            typename IncomingMappedType>
-  AddResult Insert(IncomingKeyType&&, IncomingMappedType&&);
-
   template <typename IncomingKeyType>
   static bool IsValidKey(const IncomingKeyType&);
 
@@ -577,24 +565,6 @@ typename HashMap<T, U, V, W, X, Y>::AddResult HashMap<T, U, V, W, X, Y>::Set(
   return result;
 }
 
-template <typename T,
-          typename U,
-          typename V,
-          typename W,
-          typename X,
-          typename Y>
-template <typename HashTranslator,
-          typename IncomingKeyType,
-          typename IncomingMappedType>
-auto HashMap<T, U, V, W, X, Y>::Insert(IncomingKeyType&& key,
-                                       IncomingMappedType&& mapped)
-    -> AddResult {
-  return impl_.template AddPassingHashCode<
-      HashMapTranslatorAdapter<ValueTraits, HashTranslator>>(
-      std::forward<IncomingKeyType>(key),
-      std::forward<IncomingMappedType>(mapped));
-}
-
 template <typename T,
           typename U,
           typename V,