Enable "Offer to translate" for each language item.

Add native read/write functions for language's blocked state. Once the
user selects the enabled menu item, it will toggle the state.

Demo link:
https://googleo.users.x20web.corp.google.com/screenrecord/lang-settings-toggle.mp4

Bug: 783049
Change-Id: I3b144d1b0c23705931b480dc9a869a0efe0dae00
Reviewed-on: https://chromium-review.googlesource.com/848753Reviewed-by: Ted Choc (back but slow, ping me) <tedchoc@chromium.org>
Commit-Queue: Leo Zhang <googleo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526879}

chrome/android/java/src/org/chromium/chrome/browser/preferences/PrefServiceBridge.java

@@ -958,6 +958,24 @@ public final class PrefServiceBridge {
         nativeMoveAcceptLanguage(languageCode, offset);
     }
 
+    /**
+     * @param languageCode A valid language code to check.
+     * @return Whether the given language is blocked by the user.
+     */
+    public boolean isBlockedLanguage(String languageCode) {
+        return nativeIsBlockedLanguage(languageCode);
+    }
+
+    /**
+     * Sets the blocked state of a given language.
+     *
+     * @param languageCode A valid language code to change.
+     * @param blocked Whether to set language blocked.
+     */
+    public void setLanguageBlockedState(String languageCode, boolean blocked) {
+        nativeSetLanguageBlockedState(languageCode, blocked);
+    }
+
     private native boolean nativeIsContentSettingEnabled(int contentSettingType);
     private native boolean nativeIsContentSettingManaged(int contentSettingType);
     private native void nativeSetContentSettingEnabled(int contentSettingType, boolean allow);
@@ -1146,6 +1164,8 @@ public final class PrefServiceBridge {
     private native void nativeGetUserAcceptLanguages(List<String> list);
     private native void nativeUpdateUserAcceptLanguages(String language, boolean add);
     private native void nativeMoveAcceptLanguage(String language, int offset);
+    private native boolean nativeIsBlockedLanguage(String language);
+    private native void nativeSetLanguageBlockedState(String language, boolean blocked);
     private native String nativeGetDownloadDefaultDirectory();
     private native void nativeSetDownloadDefaultDirectory(String directory);
 }

chrome/android/java/src/org/chromium/chrome/browser/preferences/languages/LanguageListPreference.java

@@ -49,8 +49,14 @@ public class LanguageListPreference extends Preference {
                     ArrayList<Item> menuItems = new ArrayList<>();
                     // Show "Offer to translate" option if "Chrome Translate" is enabled.
                     if (PrefServiceBridge.getInstance().isTranslateEnabled()) {
+                        // Set this row checked if the language is unblocked.
+                        int endIconResId =
+                                PrefServiceBridge.getInstance().isBlockedLanguage(info.getCode())
+                                ? 0
+                                : R.drawable.ic_check_googblue_24dp;
+                        // Add checked icon at the end.
                         menuItems.add(new Item(mContext,
-                                R.string.languages_item_option_offer_to_translate,
+                                R.string.languages_item_option_offer_to_translate, endIconResId,
                                 info.isSupported()));
                     }
 
@@ -64,7 +70,10 @@ public class LanguageListPreference extends Preference {
                 @Override
                 public void onItemSelected(Item item) {
                     if (item.getTextId() == R.string.languages_item_option_offer_to_translate) {
-                        // TODO(crbug/783049): Handle "offer to translate" event.
+                        // Toggle current blocked state of this language.
+                        boolean state = (item.getEndIconId() == 0);
+                        PrefServiceBridge.getInstance().setLanguageBlockedState(
+                                info.getCode(), !state);
                     } else if (item.getTextId() == R.string.remove) {
                         LanguagesManager.getInstance().removeFromAcceptLanguages(info.getCode());
                     }

chrome/browser/android/preferences/pref_service_bridge.cc

@@ -50,6 +50,7 @@
 #include "components/strings/grit/components_locale_settings.h"
 #include "components/translate/core/browser/translate_pref_names.h"
 #include "components/translate/core/browser/translate_prefs.h"
+#include "components/translate/core/common/translate_util.h"
 #include "components/version_info/version_info.h"
 #include "components/web_resource/web_resource_pref_names.h"
 #include "content/public/browser/browser_thread.h"
@@ -1223,6 +1224,35 @@ static void JNI_PrefServiceBridge_MoveAcceptLanguage(
   }
 }
 
+static jboolean JNI_PrefServiceBridge_IsBlockedLanguage(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jstring>& language) {
+  std::unique_ptr<translate::TranslatePrefs> translate_prefs =
+      ChromeTranslateClient::CreateTranslatePrefs(GetPrefService());
+
+  std::string language_code(ConvertJavaStringToUTF8(env, language));
+  translate::ToTranslateLanguageSynonym(&language_code);
+
+  return translate_prefs->IsBlockedLanguage(language_code);
+}
+
+static void JNI_PrefServiceBridge_SetLanguageBlockedState(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jstring>& language,
+    jboolean blocked) {
+  std::unique_ptr<translate::TranslatePrefs> translate_prefs =
+      ChromeTranslateClient::CreateTranslatePrefs(GetPrefService());
+  std::string language_code(ConvertJavaStringToUTF8(env, language));
+
+  if (blocked) {
+    translate_prefs->BlockLanguage(language_code);
+  } else {
+    translate_prefs->UnblockLanguage(language_code);
+  }
+}
+
 static ScopedJavaLocalRef<jstring>
 JNI_PrefServiceBridge_GetDownloadDefaultDirectory(
     JNIEnv* env,