Avoid some explicit WebSpeechRecognitionHandle() conversions.

Source/web/WebSpeechGrammar.cpp

Index: Source/web/WebSpeechGrammar.cpp
diff --git a/Source/web/WebSpeechGrammar.cpp b/Source/web/WebSpeechGrammar.cpp
index aea3e1632d333ca421232bc593b281251f1faa0e..a91f91300ea29f02b69f27ea53a3f258e561a35e 100644
--- a/Source/web/WebSpeechGrammar.cpp
+++ b/Source/web/WebSpeechGrammar.cpp
@@ -41,11 +41,6 @@ void WebSpeechGrammar::assign(const WebSpeechGrammar& other)
     m_private = other.m_private;
 }
 
-WebSpeechGrammar::WebSpeechGrammar(SpeechGrammar* value)
-    : m_private(value)
-{
-}
-
 WebSpeechGrammar& WebSpeechGrammar::operator=(SpeechGrammar* value)
 {
     m_private = value;