Added functions |find| and |Contains| to NewLinkedHashSet

Implemented |NewLinkedHashSet::find| and |NewLinkedHashSet::Contains| and added tests

Change-Id: I2488db864e2f618899a3a4fda49a9440f1264c6c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2100558
Commit-Queue: Kei Nakashima <keinakashima@google.com>
Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#750474}

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

@@ -1082,7 +1082,8 @@ class NewLinkedHashSet {
 
   // TODO(keinakashima): implement front/back
 
-  // TODO(keinakashima): implement find, Contains after implementing iterator
+  const_iterator find(ValuePeekInType) const;
+  bool Contains(ValuePeekInType) const;
 
   // TODO(keinakahsima): implement functions related to insert
   template <typename IncomingValueType>
@@ -1140,6 +1141,21 @@ inline void NewLinkedHashSet<T>::Swap(NewLinkedHashSet& other) {
   list_.swap(other.list_);
 }
 
+template <typename T>
+typename NewLinkedHashSet<T>::const_iterator NewLinkedHashSet<T>::find(
+    ValuePeekInType value) const {
+  typename Map::const_iterator it = value_to_index_.find(value);
+
+  if (it == value_to_index_.end())
+    return end();
+  return list_.MakeConstIterator(it->value);
+}
+
+template <typename T>
+bool NewLinkedHashSet<T>::Contains(ValuePeekInType value) const {
+  return value_to_index_.Contains(value);
+}
+
 template <typename T>
 template <typename IncomingValueType>
 typename NewLinkedHashSet<T>::AddResult NewLinkedHashSet<T>::insert(

third_party/blink/renderer/platform/wtf/linked_hash_set_test.cc

@@ -108,4 +108,36 @@ TEST(NewLinkedHashSetTest, PrependOrMoveToFirst) {
   EXPECT_EQ(*it, 2);
 }
 
+TEST(NewLinkedHashSetTest, FindAndContains) {
+  using Set = NewLinkedHashSet<int>;
+  Set set;
+  set.insert(2);
+  set.AppendOrMoveToLast(2);
+  set.PrependOrMoveToFirst(1);
+  set.insert(3);
+  set.AppendOrMoveToLast(4);
+  set.insert(5);
+
+  int i = 1;
+  for (auto element : set) {
+    EXPECT_EQ(element, i);
+    i++;
+  }
+
+  Set::const_iterator it = set.find(2);
+  EXPECT_EQ(*it, 2);
+  it = set.find(3);
+  EXPECT_EQ(*it, 3);
+  it = set.find(10);
+  EXPECT_TRUE(it == set.end());
+
+  EXPECT_TRUE(set.Contains(1));
+  EXPECT_TRUE(set.Contains(2));
+  EXPECT_TRUE(set.Contains(3));
+  EXPECT_TRUE(set.Contains(4));
+  EXPECT_TRUE(set.Contains(5));
+
+  EXPECT_FALSE(set.Contains(10));
+}
+
 }  // namespace WTF