Print Preview: Make generate draft mode work again.

chrome/test/data/webui/print_preview.js

Index: chrome/test/data/webui/print_preview.js
diff --git a/chrome/test/data/webui/print_preview.js b/chrome/test/data/webui/print_preview.js
index 2743ce8ed98a97ae60ecaf0cfe1a9bf0ed4786c0..06ade98beff2fcd37acf6b75a9fbdcc9f3afa02d 100644
--- a/chrome/test/data/webui/print_preview.js
+++ b/chrome/test/data/webui/print_preview.js
@@ -1356,3 +1356,41 @@ TEST_F('PrintPreviewWebUITest', 'TestInitIssuesOneRequest', function() {
     0);
   testDone();
 });
+
+// Test the preview generator to make sure the generate draft parameter is set
+// correctly. It should be false if the only change is the page range.
+TEST_F('PrintPreviewWebUITest', 'TestGenerateDraft', function() {
+  // Use a real preview generator.
+  printPreview.previewArea_.previewGenerator_ =
+      new print_preview.PreviewGenerator(printPreview.destinationStore_,
+        printPreview.printTicketStore_, this.nativeLayer_,
+        printPreview.documentInfo_);
+
+  this.setInitialSettings();
+  this.setLocalDestinations();
+  this.setCapabilities(getCddTemplate("FooDevice"));
+
+  // The first request should set |generateDraft_| to true because there was no
+  // previous print preview draft.
+  expectEquals(
+      0,
+      printPreview.previewArea_.previewGenerator_.inFlightRequestId_);
+  expectTrue(printPreview.previewArea_.previewGenerator_.generateDraft_);

[dpapad, 2017/05/01 18:08:31]

Pasting my comment from another recent print preview CL
(https://codereview.chromium.org/2849733002#msg5).

Is there a way to avoid referring to a private variable from this test? Tests
that assert on private variables tend to test a specific implementation instead
of the observed behavior of the code they are testing.

Maybe assert that something that is observable by the user on the DOM (some
button being enabled, some message being shown etc).

+
+  // Change the page range, and |generateDraft_| should be false.
+  printPreview.printTicketStore_.pageRange.updateValue("2");
+  expectEquals(
+      1,
+      printPreview.previewArea_.previewGenerator_.inFlightRequestId_);
+  expectFalse(printPreview.previewArea_.previewGenerator_.generateDraft_);
+
+  // Change the margin type, and |generateDraft_| should be true.
+  printPreview.printTicketStore_.marginsType.updateValue(
+      print_preview.ticket_items.MarginsType.Value.NO_MARGINS);
+  expectEquals(
+      2,
+      printPreview.previewArea_.previewGenerator_.inFlightRequestId_);
+  expectTrue(printPreview.previewArea_.previewGenerator_.generateDraft_);
+
+  testDone();
+});