Declaration of sha1HashSize variable in proper file

Source/wtf/SHA1.h

Index: Source/wtf/SHA1.h
diff --git a/Source/wtf/SHA1.h b/Source/wtf/SHA1.h
index d73de9815cb82a2af68caf3a6a46122e4e1ab8fd..590605edb661ff7ddaeb2e1e75c7ae60d8c53b15 100644
--- a/Source/wtf/SHA1.h
+++ b/Source/wtf/SHA1.h
@@ -57,8 +57,10 @@ public:
     }
     void addBytes(const uint8_t* input, size_t length);
 
+    static const size_t outputSizeBytes = 20;
+
     // computeHash has a side effect of resetting the state of the object.
-    void computeHash(Vector<uint8_t, 20>&);
+    void computeHash(Vector<uint8_t, outputSizeBytes>&);
 
 private:
     void finalize();