Use "unsigned" rather than "unsigned long" for C++ code interacting with WebIDL's "unsigned long".

Source/modules/speech/SpeechRecognitionResult.h

Index: Source/modules/speech/SpeechRecognitionResult.h
diff --git a/Source/modules/speech/SpeechRecognitionResult.h b/Source/modules/speech/SpeechRecognitionResult.h
index dfc3ddf99459ef68c8e852097ebb4e2831baddc9..0751d19cba33ade64b569b8890646759b73d0330 100644
--- a/Source/modules/speech/SpeechRecognitionResult.h
+++ b/Source/modules/speech/SpeechRecognitionResult.h
@@ -37,8 +37,8 @@ class SpeechRecognitionResult final : public GarbageCollected<SpeechRecognitionR
 public:
     static SpeechRecognitionResult* create(const HeapVector<Member<SpeechRecognitionAlternative> >&, bool final);
 
-    unsigned long length() { return m_alternatives.size(); }
-    SpeechRecognitionAlternative* item(unsigned long index);
+    unsigned length() { return m_alternatives.size(); }
+    SpeechRecognitionAlternative* item(unsigned index);
     bool isFinal() { return m_final; }
 
     void trace(Visitor*);