Make the gtk download shelf autoclose on mouse out.

gfx/insets.h

Index: gfx/insets.h
diff --git a/gfx/insets.h b/gfx/insets.h
index ba6cb583f45e1a4b8e367c178faa26fefc87e10b..081def19744caf675488c144e755ecfa672561fc 100644
--- a/gfx/insets.h
+++ b/gfx/insets.h
@@ -29,6 +29,16 @@ class Insets {
         left_(left),
         bottom_(bottom),
         right_(right) {}
+  Insets(int top_bottom, int left_right)
+      : top_(top_bottom),
+        left_(left_right),
+        bottom_(top_bottom),
+        right_(left_right) {}
+  explicit Insets(int inset)
+      : top_(inset),
+        left_(inset),
+        bottom_(inset),
+        right_(inset) {}
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   explicit Insets(const GtkBorder& border)
       : top_(border.top),