Check for RPCS printers and return error if Win8+

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

Index: chrome/browser/resources/print_preview/previewarea/preview_area.js
diff --git a/chrome/browser/resources/print_preview/previewarea/preview_area.js b/chrome/browser/resources/print_preview/previewarea/preview_area.js
index ca553a7c7a1102a1c5cf4aee36ab9b713ccaa22f..ec5fde1e8c73a31b4ad72702c9c779227c8a88af 100644
--- a/chrome/browser/resources/print_preview/previewarea/preview_area.js
+++ b/chrome/browser/resources/print_preview/previewarea/preview_area.js
@@ -306,6 +306,14 @@ cr.define('print_preview', function() {
      */
     showCustomMessage: function(message) {
       this.showMessage_(PreviewArea.MessageId_.CUSTOM, message);
+      if (message == loadTimeData.getString('invalidPrinterSettings') &&

[Lei Zhang, 2017/03/08 20:27:22]

Is there ever a case where we want to show a message, and then let "preview
loading..." overwrite the error message?

[rbpotter, 2017/03/08 23:25:25]

Probably not. This shouldn't occur for the other 2 calls to this
function though, as one is after we save to PDF and the other is
when we display the PDF in PDF viewer. The specific issue here is
that there is a race between the "Destination Capabilities" event
(which sets a timeout to display "Loading Preview") and the
Invalid Settings event, which leads to this function being
called. Occasionally the invalid settings event gets there after
the timeout has expired and displays as expected but most of the
time it seems to arrive after the capabilities event but before
the timeout expires, and therefore gets overwritten.

Adding dpapad to verify this addition makes sense as a fix for
that race.

+          this.loadingTimeout_) {
+        // Stop trying to generate the preview so that "preview loading..."
+        // does not overwrite the error message. Should not preview for an
+        // invalid printer.
+        clearTimeout(this.loadingTimeout_);
+        this.loadingTimeout_ = null;
+      }
     },
 
     /** @override */