Fix unused functions warnings on Linux.

Source/core/page/DragController.cpp

Index: Source/core/page/DragController.cpp
diff --git a/Source/core/page/DragController.cpp b/Source/core/page/DragController.cpp
index 085639885614a25df9e5404f6aa97b38a12583cb..cd72b05e4c4fa8b0f1091e015eb72f62aa7a1ef6 100644
--- a/Source/core/page/DragController.cpp
+++ b/Source/core/page/DragController.cpp
@@ -92,21 +92,6 @@ static const int MaxOriginalImageArea = 1500 * 1500;
 static const int LinkDragBorderInset = 2;
 static const float DragImageAlpha = 0.75f;
 
-static bool dragTypeIsValid(DragSourceAction action)
-{
-    switch (action) {
-    case DragSourceActionDHTML:
-    case DragSourceActionImage:
-    case DragSourceActionLink:
-    case DragSourceActionSelection:
-        return true;
-    case DragSourceActionNone:
-        return false;
-    }
-    // Make sure MSVC doesn't complain that not all control paths return a value.
-    return false;
-}
-
 static PlatformMouseEvent createMouseEvent(DragData* dragData)
 {
     bool shiftKey, ctrlKey, altKey, metaKey;