[TTS] Add server control from a field_trial param.

chrome/browser/android/contextualsearch/contextual_search_field_trial.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_CONTEXTUALSEARCH_CONTEXTUAL_SEARCH_FIELD_TRIAL_H_
 #define CHROME_BROWSER_ANDROID_CONTEXTUALSEARCH_CONTEXTUAL_SEARCH_FIELD_TRIAL_H_
 
 #include <stddef.h>
 
 #include "base/values.h"
@@ skipping 20 matching lines @@
 
   // Gets whether sending the URL of the base page is disabled.
   bool IsSendBasePageURLDisabled();
 
   // Gets whether decoding the mentions fields in the Resolve is disabled.
   bool IsDecodeMentionsDisabled();
 
   // Gets whether Bar integration with Contextual Cards data is enabled.
   bool IsContextualCardsBarIntegrationEnabled();
 
+  // Gets an explicit version to use for Contextual Cards integration, or 0 if
+  // not set.
+  int GetContextualCardsVersion();
+
   // Disables the cache.
   void DisableCache();
 
   // Constant used in tests.
   static const int kContextualSearchDefaultIcingSurroundingSize;
 
  protected:
   // Checks if command-line switch of the given name exists.
   virtual bool HasSwitch(const std::string& name);
 
@@ skipping 16 matching lines @@
   // Caches the result pointed to by the given |cached_value|, using the given
   // |is_value_cached| to remember if the value has been cached or not.
   int GetIntParamValueOrDefault(const std::string& param_name,
                                 const int default_value,
                                 bool* is_value_cached,
                                 int* cached_value);
 
   // Cached values.
   bool is_resolver_url_prefix_cached_;
   std::string resolver_url_prefix_;
+
   bool is_surrounding_size_cached_;
   int surrounding_size_;
+
   bool is_icing_surrounding_size_cached_;
   int icing_surrounding_size_;
+
   bool is_send_base_page_url_disabled_cached_;
   bool is_send_base_page_url_disabled_;
+
   bool is_decode_mentions_disabled_cached_;
   bool is_decode_mentions_disabled_;
+
   bool is_contextual_cards_bar_integration_enabled_cached_;
   bool is_contextual_cards_bar_integration_enabled_;
 
+  bool is_contextual_cards_version_cached_;
+  int contextual_cards_version_;
+
   DISALLOW_COPY_AND_ASSIGN(ContextualSearchFieldTrial);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_CONTEXTUALSEARCH_CONTEXTUAL_SEARCH_FIELD_TRIAL_H_