Enable speech input by default and remove unused code.

chrome/browser/speech/speech_input_manager.h

Index: chrome/browser/speech/speech_input_manager.h
diff --git a/chrome/browser/speech/speech_input_manager.h b/chrome/browser/speech/speech_input_manager.h
index ffeaba0d700f3251857b899f24da8f7fc933bba0..be9779ff73211dd4fb62ff7b9aeb3de076721cf8 100644
--- a/chrome/browser/speech/speech_input_manager.h
+++ b/chrome/browser/speech/speech_input_manager.h
@@ -32,10 +32,6 @@ class SpeechInputManager {
     virtual ~Delegate() {}
   };
 
-  // Whether the speech input feature is enabled, based on the browser channel
-  // information and command line flags.
-  static bool IsFeatureEnabled();
-
   // Factory method to access the singleton. We have this method here instead of
   // using Singleton<> directly in the calling code to aid tests in injection
   // mocks.