Print Preview: Change print to cr.sendWithPromise

chrome/test/data/webui/print_preview/print_preview_tests.js

Index: chrome/test/data/webui/print_preview/print_preview_tests.js
diff --git a/chrome/test/data/webui/print_preview/print_preview_tests.js b/chrome/test/data/webui/print_preview/print_preview_tests.js
index 33ddef39b060097a8a8edc667aa041f549d58213..d958a30daae3634ec748dfad984f715919223335 100644
--- a/chrome/test/data/webui/print_preview/print_preview_tests.js
+++ b/chrome/test/data/webui/print_preview/print_preview_tests.js
@@ -1307,9 +1307,9 @@ cr.define('print_preview_test', function() {
               // Has active print button and successfully 'prints', indicating
               // recovery from error state.
               expectFalse(printButton.disabled);
-              expectFalse(nativeLayer.isPrintStarted());
               printButton.click();
-              expectTrue(nativeLayer.isPrintStarted());
+              // This should result in a call to print.
+              return nativeLayer.whenCalled('print');

[dpapad, 2017/06/23 00:13:57]

Related to comment in native_layer_stub.js, here we could be asserting that
nativeLayer.print() was called correctly.

             });
       });
     });