[CUPS] Add a "Manage..." button in the local destinations section of Print Preview Dialog on Chrome…

chrome/browser/resources/print_preview/print_preview.js

Index: chrome/browser/resources/print_preview/print_preview.js
diff --git a/chrome/browser/resources/print_preview/print_preview.js b/chrome/browser/resources/print_preview/print_preview.js
index f220da8eaeb845729eb80a29096f610b74a8c73a..21fecce6aae3b355f7bda7d23cd63f00d7f11d57 100644
--- a/chrome/browser/resources/print_preview/print_preview.js
+++ b/chrome/browser/resources/print_preview/print_preview.js
@@ -963,6 +963,10 @@ cr.define('print_preview', function() {
      * @private
      */
     onManageLocalDestinationsActivated_: function() {
+      if (cr.isChromeOS && loadTimeData.getBoolean('showLocalManageButton')) {

[Dan Beam, 2016/09/21 20:56:25]

if (loadTimeData.valueExists('localPrintersManagementURL'))
  window.open(loadTimeData.getString('localPrintersManagementURL'));
else
  this.nativeLayer_.startManageLocalDestinations();

[dpapad, 2016/09/21 20:58:23]

I think the confusing part is here. Why would this listener execute if
loadTimeData.getBoolean('showLocalManageButton') is false in the first place?
Wouldn't that cause the button to never be even shown?

I think 'showLocalManageButton' naming is confusing. Would renaming as something
as 'showWebUICupsConfig' make more sense? Then it would be

if (cr.isChromeOS && loadTimeData.getBoolean('showWebUICupsConfig')) {
...
}

[xdai1, 2016/09/21 23:38:53]

You're right that we won't get the event in the first place if
loadTimeData.getBoolean('showLocalManageButton') is false. Since
'showLocalManageButton' can only be false on Chrome OS, maybe we only check if
it's Chromeos?

[dpapad, 2016/09/22 00:18:15]

That looks fine. Alternatively, we could just do this check in C++ instead, and
open the new tab in a similar manner as
https://cs.chromium.org/chromium/src/chrome/browser/ui/webui/print_preview/pr....
The benefit is that localPrintersManagementURL would not need to be passed to JS
at all, and we would trade a Javascript runtime isChromeOS check with a
compile-time C++ ifdef.

This is still LG as-is. Up to you if you want to handle the event in C++
instead.

+        window.open(loadTimeData.getString('localPrintersManagementURL'));
+        return;
+      }
       this.nativeLayer_.startManageLocalDestinations();
     },