Add "AllArticles" mode to Reader Mode heuristics

chrome/browser/flag_descriptions.h

 // 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.
 
 #ifndef CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 #define CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 
 // Includes needed for macros allowing conditional compilation of some strings.
 #include "build/build_config.h"
 #include "build/buildflag.h"
@@ skipping 1077 matching lines @@
 extern const char
     kProgressBarCompletionResourcesBeforeDclAndSameOriginIframes[];
 
 extern const char kPullToRefreshEffectName[];
 extern const char kPullToRefreshEffectDescription[];
 
 extern const char kReaderModeHeuristicsName[];
 extern const char kReaderModeHeuristicsDescription[];
 extern const char kReaderModeHeuristicsMarkup[];
 extern const char kReaderModeHeuristicsAdaboost[];
+extern const char kReaderModeHeuristicsAllArticles[];
 extern const char kReaderModeHeuristicsAlwaysOff[];
 extern const char kReaderModeHeuristicsAlwaysOn[];
 
 extern const char kServiceWorkerPaymentAppsName[];
 extern const char kServiceWorkerPaymentAppsDescription[];
 
 extern const char kSetMarketUrlForTestingName[];
 extern const char kSetMarketUrlForTestingDescription[];
 
 extern const char kTabsInCbdName[];
@@ skipping 420 matching lines @@
 #endif  // defined(TOOLKIT_VIEWS) || defined(OS_ANDROID)
 
 // ============================================================================
 // Don't just add flags to the end, put them in the right section in
 // alphabetical order. See top instructions for more.
 // ============================================================================
 
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_