Delete the old hotwording integration.

chrome/browser/search/hotword_service.h

Index: chrome/browser/search/hotword_service.h
diff --git a/chrome/browser/search/hotword_service.h b/chrome/browser/search/hotword_service.h
index 2c0e086ba12c99f80ae2c522cc5e681ecea7649f..b659371f05c8d5236729947d7034e1ed3931f34e 100644
--- a/chrome/browser/search/hotword_service.h
+++ b/chrome/browser/search/hotword_service.h
@@ -60,10 +60,6 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
   // Returns true if the hotword supports the current system language.
   static bool DoesHotwordSupportLanguage(Profile* profile);
 
-  // Always returns true.
-  // TODO(amistry): Remove this.
-  static bool IsExperimentalHotwordingEnabled();
-
   explicit HotwordService(Profile* profile);
   ~HotwordService() override;
 
@@ -96,14 +92,6 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
   // Returns whether google.com/NTP/launcher hotwording is enabled.
   bool IsSometimesOnEnabled();
 
-  // Control the state of the hotword extension.
-  void EnableHotwordExtension(ExtensionService* extension_service);
-  void DisableHotwordExtension(ExtensionService* extension_service);
-
-  // Handles enabling/disabling the hotword extension when the user
-  // turns it off via the settings menu.
-  void OnHotwordSearchEnabledChanged(const std::string& pref_name);
-
   // Handles enabling/disabling the hotword notification when the user
   // changes the always on search settings.
   void OnHotwordAlwaysOnSearchEnabledChanged(const std::string& pref_name);