Fixed all unused-variable Clang warnings on Windows.

ui/app_list/views/app_list_item_view.cc

Index: ui/app_list/views/app_list_item_view.cc
diff --git a/ui/app_list/views/app_list_item_view.cc b/ui/app_list/views/app_list_item_view.cc
index e6b55bfac8f21ac28690243667a16fc5498f702f..c5a8b3338c854780ef496a4dbd52eeaefbadebea 100644
--- a/ui/app_list/views/app_list_item_view.cc
+++ b/ui/app_list/views/app_list_item_view.cc
@@ -49,8 +49,10 @@ const int kFolderPreviewRadius = 40;
 
 const int kLeftRightPaddingChars = 1;
 
+#if !defined(OS_WIN)
 // Scale to transform the icon when a drag starts.
 const float kDraggingIconScale = 1.5f;
+#endif
 
 // Delay in milliseconds of when the dragging UI should be shown for mouse drag.
 const int kMouseDragUIDelayInMs = 200;