Implement equality methods for CWVTranslationLanguage

This will make them easier to work with when used in collections

Change-Id: I8225afc3076929c9d8c162ca2a4af30c390e7fd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2425400
Commit-Queue: John Wu <jzw@chromium.org>
Reviewed-by: Hiroshi Ichikawa <ichikawa@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810253}

ios/web_view/internal/translate/cwv_translation_language.mm

@@ -29,6 +29,22 @@
   return self;
 }
 
+- (BOOL)isEqual:(id)object {
+  if (self == object) {
+    return YES;
+  }
+  if (![object isKindOfClass:[CWVTranslationLanguage class]]) {
+    return NO;
+  }
+
+  CWVTranslationLanguage* otherLanguage = (CWVTranslationLanguage*)object;
+  return [_languageCode isEqualToString:otherLanguage.languageCode];
+}
+
+- (NSUInteger)hash {
+  return [_languageCode hash];
+}
+
 - (NSString*)description {
   return
       [NSString stringWithFormat:@"%@ name:%@(%@) code:%@", [super description],

ios/web_view/internal/translate/cwv_translation_language_unittest.mm

@@ -34,4 +34,21 @@ TEST_F(CWVTranslationLanguageTest, Initialization) {
   EXPECT_NSEQ(native_name, language.nativeName);
 }
 
+TEST_F(CWVTranslationLanguageTest, Equality) {
+  // Two languages with the same langauge code but different localized/native
+  // names.
+  CWVTranslationLanguage* language_a = [[CWVTranslationLanguage alloc]
+      initWithLanguageCode:"ja"
+             localizedName:base::SysNSStringToUTF16(@"JapaneseA")
+                nativeName:base::SysNSStringToUTF16(@"日本語A")];
+  CWVTranslationLanguage* language_b = [[CWVTranslationLanguage alloc]
+      initWithLanguageCode:"ja"
+             localizedName:base::SysNSStringToUTF16(@"JapaneseB")
+                nativeName:base::SysNSStringToUTF16(@"日本語B")];
+
+  // Equality should only be based on the language code.
+  EXPECT_NSEQ(language_a, language_b);
+  EXPECT_EQ(language_a.hash, language_b.hash);
+}
+
 }  // namespace ios_web_view