Integrate new MD update menu icons.

ui/gfx/vector_icons/update_menu_severity_warning.icon

Index: ui/gfx/vector_icons/update_menu_severity_warning.icon
diff --git a/ui/gfx/vector_icons/checkbox_active.icon b/ui/gfx/vector_icons/update_menu_severity_warning.icon
similarity index 55%
copy from ui/gfx/vector_icons/checkbox_active.icon
copy to ui/gfx/vector_icons/update_menu_severity_warning.icon
index 480303791d65b69e77de8f4f648c56f8f3d04042..4ad84ef163a08cdc5e7910025d9506c5f474a3f2 100644
--- a/ui/gfx/vector_icons/checkbox_active.icon
+++ b/ui/gfx/vector_icons/update_menu_severity_warning.icon
@@ -3,14 +3,20 @@
 // found in the LICENSE file.
 
 CANVAS_DIMENSIONS, 32,
-ROUND_RECT, 2, 2, 28, 28, 2,
+CIRCLE, 16, 16, 16,
+CLOSE,
 NEW_PATH,
 PATH_COLOR_ARGB, 0xFF, 0xFF, 0xFF, 0xFF,
-MOVE_TO, 14, 24,
-R_LINE_TO, -8, -8,
-R_LINE_TO, 2, -2,
-R_LINE_TO, 6, 6,
-LINE_TO, 26, 8,
-R_LINE_TO, 2, 2,
+MOVE_TO, 18, 16,
+R_H_LINE_TO, -4,
+V_LINE_TO, 8,
+R_H_LINE_TO, 4,
+R_V_LINE_TO, 8,
+CLOSE,
+R_MOVE_TO, 0, 8,
+R_H_LINE_TO, -4,
+R_V_LINE_TO, -4,
+R_H_LINE_TO, 4,
+R_V_LINE_TO, 4,
 CLOSE,
-END
+END