Expose method to reset translate settings.

ios/web_view/internal/cwv_web_view_configuration.mm

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/web_view/public/cwv_web_view_configuration.h"
 #import "ios/web_view/internal/cwv_web_view_configuration_internal.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/threading/thread_restrictions.h"
-#include "components/translate/core/browser/translate_download_manager.h"
+#include "components/translate/core/browser/translate_prefs.h"
 #include "ios/web_view/internal/app/application_context.h"
 #import "ios/web_view/internal/cwv_user_content_controller_internal.h"
+#include "ios/web_view/internal/pref_names.h"
 #include "ios/web_view/internal/web_view_browser_state.h"
 #include "ios/web_view/internal/web_view_global_state_util.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 @interface CWVWebViewConfiguration () {
   // The BrowserState for this configuration.
   std::unique_ptr<ios_web_view::WebViewBrowserState> _browserState;
@@ skipping 32 matching lines @@
   self = [super init];
   if (self) {
     _browserState = std::move(browserState);
 
     _userContentController =
         [[CWVUserContentController alloc] initWithConfiguration:self];
   }
   return self;
 }
 
+#pragma mark - Public Methods
+
+- (void)resetTranslationPreferences {
+  translate::TranslatePrefs translatePrefs(_browserState->GetPrefs(),
+                                           prefs::kAcceptLanguages, nullptr);
+  translatePrefs.ResetToDefaults();
+}
+
 - (BOOL)isPersistent {
   return !_browserState->IsOffTheRecord();
 }
 
+#pragma mark - Private Methods
+
 - (ios_web_view::WebViewBrowserState*)browserState {
   return _browserState.get();
 }
 
 @end