[TTS] Add server control from a field_trial param.

chrome/browser/android/contextualsearch/contextual_search_delegate.cc

Index: chrome/browser/android/contextualsearch/contextual_search_delegate.cc
diff --git a/chrome/browser/android/contextualsearch/contextual_search_delegate.cc b/chrome/browser/android/contextualsearch/contextual_search_delegate.cc
index 765b165126a3ba7ff7b7e56d7c259484bfefb09a..ac4e178455ee64326ee6ed8113013a0ee6356451 100644
--- a/chrome/browser/android/contextualsearch/contextual_search_delegate.cc
+++ b/chrome/browser/android/contextualsearch/contextual_search_delegate.cc
@@ -72,8 +72,6 @@ const int kContextualCardsNoIntegration = 0;
 const int kContextualCardsBarIntegration = 1;
 const int kContextualCardsSingleAction = 2;
 
-const char kContextualCardsVersionOverride[] = "contextual_cards_version";
-
 }  // namespace
 
 // URLFetcher ID, only used for tests: we only have one kind of fetcher.
@@ -240,11 +238,8 @@ std::string ContextualSearchDelegate::BuildRequestUrl(
     contextual_cards_version = kContextualCardsSingleAction;
   }
 
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-      kContextualCardsVersionOverride)){
-    contextual_cards_version =
-        std::stoi(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-            kContextualCardsVersionOverride), nullptr);
+  if (field_trial_->GetContextualCardsVersion() != 0) {
+    contextual_cards_version = field_trial_->GetContextualCardsVersion();
   }
 
   TemplateURLRef::SearchTermsArgs::ContextualSearchParams params(