Replace OnPageTranslate Obsever by a responder of delegate.

components/translate/core/browser/translate_infobar_delegate.h

 // 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.
 
 #ifndef COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_INFOBAR_DELEGATE_H_
 #define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_INFOBAR_DELEGATE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 19 matching lines @@
 namespace translate {
 
 // Feature flag for "Translate Compact Infobar UI" project.
 extern const base::Feature kTranslateCompactUI;
 
 class TranslateDriver;
 class TranslateManager;
 
 class TranslateInfoBarDelegate : public infobars::InfoBarDelegate {
  public:
+  // An observer to handle different translate steps' UI changes.
+  class Observer {
+   public:
+    // Handles UI changes on the translate step given.
+    virtual void OnTranslateStepChanged(translate::TranslateStep step,
+                              TranslateErrors::Type error_type){};
+    // Return whether user declined translate service.
+    virtual bool IsDeclinedByUser();
+
+   protected:
+    virtual ~Observer() {}
+  };
+
   static const size_t kNoIndex;
 
   ~TranslateInfoBarDelegate() override;
 
   // Factory method to create a translate infobar.  |error_type| must be
   // specified iff |step| == TRANSLATION_ERROR.  For other translate steps,
   // |original_language| and |target_language| must be ASCII language codes
   // (e.g. "en", "fr", etc.) for languages the TranslateManager supports
   // translating.  The lone exception is when the user initiates translation
   // from the context menu, in which case it's legal to call this with
@@ skipping 125 matching lines @@
   // been translate to <lang2> from <lang1>."). It is ignored if
   // |autodetermined_source_language| is true.
   static void GetAfterTranslateStrings(std::vector<base::string16>* strings,
                                        bool* swap_languages,
                                        bool autodetermined_source_language);
 
   // Gets the TranslateDriver associated with this object.
   // May return NULL if the driver has been destroyed.
   TranslateDriver* GetTranslateDriver();
 
+  // Set a observer.
+  void SetObserver(Observer* observer);
+
  protected:
   TranslateInfoBarDelegate(
       const base::WeakPtr<TranslateManager>& translate_manager,
       bool is_off_the_record,
       translate::TranslateStep step,
       const std::string& original_language,
       const std::string& target_language,
       TranslateErrors::Type error_type,
       bool triggered_from_menu);
 
@@ skipping 17 matching lines @@
   // The error that occurred when trying to translate (NONE if no error).
   TranslateErrors::Type error_type_;
 
   // The translation related preferences.
   std::unique_ptr<TranslatePrefs> prefs_;
 
   // Whether the translation was triggered via a menu click vs automatically
   // (due to language detection, preferences...)
   bool triggered_from_menu_;
 
+  // A observer to handle front-end changes on different steps.
+  // It's only used when we try to reuse the existing UI.
+  Observer* observer_;
+
   DISALLOW_COPY_AND_ASSIGN(TranslateInfoBarDelegate);
 };
 
 }  // namespace translate
 
 #endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_INFOBAR_DELEGATE_H_