Remove OS(IOS) and OS(MAC_OS_X) guards.

Source/core/html/shadow/SpinButtonElement.cpp

Index: Source/core/html/shadow/SpinButtonElement.cpp
diff --git a/Source/core/html/shadow/SpinButtonElement.cpp b/Source/core/html/shadow/SpinButtonElement.cpp
index 3a637d0c8d6918b9151d611c161fe9ad45570820..55b3ef1070d89622837c4b0a352cb91fb7668dbf 100644
--- a/Source/core/html/shadow/SpinButtonElement.cpp
+++ b/Source/core/html/shadow/SpinButtonElement.cpp
@@ -236,7 +236,7 @@ void SpinButtonElement::step(int amount)
     // On Mac OS, NSStepper updates the value for the button under the mouse
     // cursor regardless of the button pressed at the beginning. So the
     // following check is not needed for Mac OS.
-#if !OS(MAC_OS_X)
+#if !OS(DARWIN)
     if (m_upDownState != m_pressStartingState)
         return;
 #endif