Replace OnPageTranslate Obsever by a responder of delegate.

chrome/browser/ui/android/infobars/translate_compact_infobar.cc

 // 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.
 
 #include "chrome/browser/ui/android/infobars/translate_compact_infobar.h"
 
 #include <stddef.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/translate/android/translate_utils.h"
 #include "components/translate/core/browser/translate_infobar_delegate.h"
 #include "jni/TranslateCompactInfoBar_jni.h"
 
 using base::android::JavaParamRef;
 using base::android::ScopedJavaLocalRef;
 
 // TranslateInfoBar -----------------------------------------------------------
 
 TranslateCompactInfoBar::TranslateCompactInfoBar(

[napper, 2017/05/19 00:17:50]

Dont you need to initialize action_flags_ here?

[Leo, 2017/05/19 03:30:23]

Acknowledged.

     std::unique_ptr<translate::TranslateInfoBarDelegate> delegate)
     : InfoBarAndroid(std::move(delegate)) {
-  // |translate_driver| must already be bound.
-  DCHECK(GetDelegate()->GetTranslateDriver());
-  translate_driver_ = static_cast<translate::ContentTranslateDriver*>(
-      GetDelegate()->GetTranslateDriver());
-  translate_driver_->AddObserver(this);
+  GetDelegate()->SetResponder(this);
 }
 
 TranslateCompactInfoBar::~TranslateCompactInfoBar() {
-  DCHECK(translate_driver_);
-  translate_driver_->RemoveObserver(this);
+  GetDelegate()->SetResponder(nullptr);
 }
 
 ScopedJavaLocalRef<jobject> TranslateCompactInfoBar::CreateRenderInfoBar(
     JNIEnv* env) {
   translate::TranslateInfoBarDelegate* delegate = GetDelegate();
 
   base::android::ScopedJavaLocalRef<jobjectArray> java_languages =
       TranslateUtils::GetJavaLanguages(env, delegate);
   base::android::ScopedJavaLocalRef<jobjectArray> java_codes =
       TranslateUtils::GetJavaLanguageCodes(env, delegate);
@@ skipping 14 matching lines @@
       java_hash_codes);
 }
 
 void TranslateCompactInfoBar::ProcessButton(int action) {
   if (!owner())
     return;  // We're closing; don't call anything, it might access the owner.
 
   // TODO(ramyasharma): Handle other button clicks.
   translate::TranslateInfoBarDelegate* delegate = GetDelegate();
   if (action == InfoBarAndroid::ACTION_TRANSLATE) {
+    action_flags |= FLAG_TRANSLATE;
     delegate->Translate();
     if (!delegate->ShouldAlwaysTranslate() && ShouldAutoAlwaysTranslate()) {
       JNIEnv* env = base::android::AttachCurrentThread();
       Java_TranslateCompactInfoBar_setAutoAlwaysTranslate(env,
                                                           GetJavaInfoBar());
     }
   } else if (action == InfoBarAndroid::ACTION_TRANSLATE_SHOW_ORIGINAL) {
+    action_flags |= FLAG_REVERT;
     delegate->RevertTranslation();
   } else if (action == InfoBarAndroid::ACTION_CANCEL) {
     delegate->TranslationDeclined();
   } else {
     DCHECK_EQ(InfoBarAndroid::ACTION_NONE, action);
   }
 }
 
 void TranslateCompactInfoBar::SetJavaInfoBar(
     const base::android::JavaRef<jobject>& java_info_bar) {
@@ skipping 25 matching lines @@
 }
 
 void TranslateCompactInfoBar::ApplyBoolTranslateOption(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,
     int option,
     jboolean value) {
   translate::TranslateInfoBarDelegate* delegate = GetDelegate();
   if (option == TranslateUtils::OPTION_ALWAYS_TRANSLATE) {
     if (delegate->ShouldAlwaysTranslate() != value) {
+      action_flags |= FLAG_ALWAYS_TRANSLATE;
       delegate->ToggleAlwaysTranslate();
     }
   } else if (option == TranslateUtils::OPTION_NEVER_TRANSLATE) {
     if (value && delegate->IsTranslatableLanguageByPrefs()) {
+      action_flags |= FLAG_NEVER_LANGUAGE;
       delegate->ToggleTranslatableLanguageByPrefs();
     }
   } else if (option == TranslateUtils::OPTION_NEVER_TRANSLATE_SITE) {
     if (value && !delegate->IsSiteBlacklisted()) {
+      action_flags |= FLAG_NEVER_SITE;
       delegate->ToggleSiteBlacklist();
     }
   } else {
     DCHECK(false);
   }
 }
 
-void TranslateCompactInfoBar::OnPageTranslated(
-    const std::string& original_lang,
-    const std::string& translated_lang,
-    translate::TranslateErrors::Type error_type) {
-  if (!owner())
-    return;  // We're closing; don't call anything, it might access the owner.
-
-  DCHECK(translate_driver_);
-  JNIEnv* env = base::android::AttachCurrentThread();
-  Java_TranslateCompactInfoBar_onPageTranslated(env, GetJavaInfoBar(),
-                                                error_type);
-}
-
 bool TranslateCompactInfoBar::ShouldAutoAlwaysTranslate() {
   translate::TranslateInfoBarDelegate* delegate = GetDelegate();
   return (delegate->GetTranslationAcceptedCount() == kAcceptCountThreshold);
 }
 
 jboolean TranslateCompactInfoBar::ShouldAutoNeverTranslate(
     JNIEnv* env,
     const base::android::JavaParamRef<jobject>& obj) {
   translate::TranslateInfoBarDelegate* delegate = GetDelegate();
   return (delegate->GetTranslationDeniedCount() == kDeniedCountThreshold);
 }
 
 translate::TranslateInfoBarDelegate* TranslateCompactInfoBar::GetDelegate() {
   return delegate()->AsTranslateInfoBarDelegate();
 }
 
+void TranslateCompactInfoBar::ActionOnStep(
+    translate::TranslateStep step,
+    translate::TranslateErrors::Type error_type) {
+  if (!owner())
+    return;  // We're closing; don't call anything.
+
+  if ((step == translate::TRANSLATE_STEP_AFTER_TRANSLATE) ||
+      (step == translate::TRANSLATE_STEP_TRANSLATE_ERROR)) {
+    JNIEnv* env = base::android::AttachCurrentThread();

[napper, 2017/05/19 00:17:50]

Can this be:

const JNIEnv* const env ...

or at least:

JNIEnv* const env ...

[Leo, 2017/05/19 03:30:23]

Not sure whether JNI framework has treated the env args as const in method
Java_Class*_Method*

But I checked all usages. None of them set const for the env.
https://cs.chromium.org/search/?q=AttachCurrentThread&type=cs 

+    Java_TranslateCompactInfoBar_onPageTranslated(env, GetJavaInfoBar(),
+                                                  error_type);
+  }
+}
+
+bool TranslateCompactInfoBar::Declined() {
+  return action_flags == 0;

[napper, 2017/05/19 00:17:50]

It might be clearer if you had:

FLAG_NONE = 0

then 

return action_flags == FLAG_NONE;

[Leo, 2017/05/19 03:30:23]

Acknowledged.

+};
+
 // Native JNI methods ---------------------------------------------------------
 
 // static
 bool RegisterTranslateCompactInfoBar(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }