Implemented new Translate API for purely Objective-C clients.

ios/web_view/internal/translate/cwv_translate_manager_impl.mm

-// Copyright 2014 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/internal/translate/cwv_translate_manager_impl.h"
-
-#include "base/logging.h"
-#include "base/memory/ptr_util.h"
-#include "components/translate/core/browser/translate_manager.h"
-#include "components/translate/core/browser/translate_ui_delegate.h"
-
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
-
-@implementation CWVTranslateManagerImpl {
-  std::unique_ptr<translate::TranslateUIDelegate> _translateUIDelegate;
-}
-
-- (instancetype)initWithTranslateManager:(translate::TranslateManager*)manager
-                          sourceLanguage:(const std::string&)source
-                          targetLanguage:(const std::string&)target {
-  if ((self = [super init])) {
-    DCHECK(manager);
-    _translateUIDelegate = base::MakeUnique<translate::TranslateUIDelegate>(
-        manager->GetWeakPtr(), source, target);
-  }
-  return self;
-}
-
-#pragma mark CWVTranslateManager methods
-
-- (void)translate {
-  _translateUIDelegate->Translate();
-}
-
-- (void)revertTranslation {
-  _translateUIDelegate->RevertTranslation();
-}
-
-@end