Replace OnPageTranslate Obsever by a responder of delegate.

components/translate/core/browser/translate_infobar_delegate.cc

Index: components/translate/core/browser/translate_infobar_delegate.cc
diff --git a/components/translate/core/browser/translate_infobar_delegate.cc b/components/translate/core/browser/translate_infobar_delegate.cc
index 1ca24c8e7dda38048ce612f9df423a68aebf6bba..ae85203d0293284d0b694c2c2f095bc5ffeac273 100644
--- a/components/translate/core/browser/translate_infobar_delegate.cc
+++ b/components/translate/core/browser/translate_infobar_delegate.cc
@@ -101,12 +101,18 @@ void TranslateInfoBarDelegate::Create(
     old_infobar = infobar_manager->infobar_at(i);
     old_delegate = old_infobar->delegate()->AsTranslateInfoBarDelegate();
     if (old_delegate) {
-      if (!replace_existing_infobar || IsCompactUIEnabled())
+      if (!replace_existing_infobar)
         return;
       break;
     }
   }
 
+  // Try to reuse existing translate infobar delegate.
+  if (old_delegate && old_delegate->observer_) {
+    old_delegate->observer_->OnTranslateStepChanged(step, error_type);
+    return;
+  }
+
   // Add the new delegate.
   TranslateClient* translate_client = translate_manager->translate_client();
   std::unique_ptr<infobars::InfoBar> infobar(translate_client->CreateInfoBar(
@@ -124,6 +130,10 @@ bool TranslateInfoBarDelegate::IsCompactUIEnabled() {
   return base::FeatureList::IsEnabled(kTranslateCompactUI);
 }
 
+void TranslateInfoBarDelegate::SetObserver(Observer* observer) {
+  observer_ = observer;
+}
+
 void TranslateInfoBarDelegate::UpdateOriginalLanguage(
     const std::string& language_code) {
   ui_delegate_.UpdateOriginalLanguage(language_code);
@@ -361,7 +371,8 @@ TranslateInfoBarDelegate::TranslateInfoBarDelegate(
       translate_manager_(translate_manager),
       error_type_(error_type),
       prefs_(translate_manager->translate_client()->GetTranslatePrefs()),
-      triggered_from_menu_(triggered_from_menu) {
+      triggered_from_menu_(triggered_from_menu),
+      observer_(nullptr) {
   DCHECK_NE((step_ == translate::TRANSLATE_STEP_TRANSLATE_ERROR),
             (error_type_ == TranslateErrors::NONE));
   DCHECK(translate_manager_);
@@ -377,13 +388,15 @@ int TranslateInfoBarDelegate::GetIconId() const {
 }
 
 void TranslateInfoBarDelegate::InfoBarDismissed() {
-  if (step_ != translate::TRANSLATE_STEP_BEFORE_TRANSLATE)
-    return;
-  if (IsCompactUIEnabled())
-    return;
-  // The user closed the infobar without clicking the translate button.
-  TranslationDeclined();
-  UMA_HISTOGRAM_BOOLEAN("Translate.DeclineTranslateCloseInfobar", true);
+  bool declined = observer_
+                      ? observer_->IsDeclinedByUser()
+                      : (step_ == translate::TRANSLATE_STEP_BEFORE_TRANSLATE);
+
+  if (declined) {
+    // The user closed the infobar without clicking the translate button.
+    TranslationDeclined();
+    UMA_HISTOGRAM_BOOLEAN("Translate.DeclineTranslateCloseInfobar", true);
+  }
 }
 
 TranslateInfoBarDelegate*