Enable speech input by default and remove unused code.

content/browser/speech/speech_input_manager.h

Index: content/browser/speech/speech_input_manager.h
diff --git a/content/browser/speech/speech_input_manager.h b/content/browser/speech/speech_input_manager.h
index 951def9fe54879948302b0254804ff6b76a74e9f..c990e8c917ea33fdcfda2a910f7b230711728959 100644
--- a/content/browser/speech/speech_input_manager.h
+++ b/content/browser/speech/speech_input_manager.h
@@ -31,10 +31,6 @@ class SpeechInputManager {
     virtual ~Delegate() {}
   };
 
-  // Whether the speech input feature is enabled, based on the browser channel
-  // information and command line flags.
-  static bool IsFeatureEnabled();
-
   // Invokes the platform provided microphone settings UI in a non-blocking way,
   // via the BrowserThread::FILE thread.
   static void ShowAudioInputSettings();