[NTP::Cleanup] Store tab id as int in SnippetArticle.

chrome/browser/android/ntp/ntp_snippets_bridge.cc

 // Copyright 2016 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/android/ntp/ntp_snippets_bridge.h"
 
 #include <jni.h>
 #include <utility>
 #include <vector>
 
@@ skipping 69 matching lines @@
         Java_SnippetsBridge_setOfflinePageDownloadDataForSuggestion(
             env, java_suggestion,
             suggestion.download_suggestion_extra()->offline_page_id);
       }
     }
     if (suggestion.id().category().IsKnownCategory(
             KnownCategories::RECENT_TABS) &&
         suggestion.recent_tab_suggestion_extra() != nullptr) {
       Java_SnippetsBridge_setRecentTabDataForSuggestion(
           env, java_suggestion,
-          ConvertUTF8ToJavaString(
-              env, suggestion.recent_tab_suggestion_extra()->tab_id),
+          suggestion.recent_tab_suggestion_extra()->tab_id,
           suggestion.recent_tab_suggestion_extra()->offline_page_id);
     }
   }
 
   return result;
 }
 
 ntp_snippets::RemoteSuggestionsScheduler* GetRemoteSuggestionsScheduler() {
   ntp_snippets::ContentSuggestionsService* content_suggestions_service =
       ContentSuggestionsServiceFactory::GetForProfile(
@@ skipping 383 matching lines @@
   JNIEnv* env = AttachCurrentThread();
   Java_SnippetsBridge_onMoreSuggestions(
       env, bridge_, category.id(),
       ToJavaSuggestionList(env, category, suggestions));
 }
 
 // static
 bool NTPSnippetsBridge::Register(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }