Added DCHECK that triggers on nullptr when creating nine_image_painter

Because it's possible to pass nullptr (|image_ids| argument via pointer)
R=sadrul@chromium.org,sky@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1680293004

Cr-Commit-Position: refs/heads/master@{#376142}

ui/base/nine_image_painter_factory.cc

@@ -14,6 +14,7 @@ namespace ui {
 namespace {
 
 std::vector<gfx::ImageSkia> ImageIdsToImages(const int image_ids[]) {
+  DCHECK(image_ids);
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   std::vector<gfx::ImageSkia> images(9);
   for (size_t i = 0; i < 9; ++i) {