Enable a11y audit for chrome://print and fix failing tests.

chrome/browser/resources/print_preview/previewarea/preview_area.css

Index: chrome/browser/resources/print_preview/previewarea/preview_area.css
diff --git a/chrome/browser/resources/print_preview/previewarea/preview_area.css b/chrome/browser/resources/print_preview/previewarea/preview_area.css
index ef12a1c2f9ebd0526de11459466c93cc764a9116..673bc87dac956ca483498c760d047510b94e63c4 100644
--- a/chrome/browser/resources/print_preview/previewarea/preview_area.css
+++ b/chrome/browser/resources/print_preview/previewarea/preview_area.css
@@ -78,3 +78,8 @@
 #preview-area .preview-area-open-system-dialog-button-throbber {
   vertical-align: middle;
 }
+
+.preview-area-overlayed {
+  visibility: hidden !important;

[Dan Beam, 2014/10/20 20:15:24]

is this debug code?  we try not to use !important whenever possible

[hcarmona, 2014/10/21 01:07:17]

Don't need "!important", removing it.

This is not debug code. It is necessary because we can't reuse the "invisible"
class as it can be overwritten and we don't want to interfere with other
functionality when hiding elements with the overlay. The visibility of all
elements should remain unchanged when the overlap is gone.

+}

[Dan Beam, 2014/10/20 20:15:24]

nit: no \n at end of file

[hcarmona, 2014/10/21 01:07:17]

Acknowledged.

+