Added a test that currently is able to print to pdf.

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 ac3a0ab789135db2746d6fe3b522398b759867d9..00aec0ad2ba9b3133c6896f003d5b9561be0f2e5 100644
--- a/chrome/browser/resources/print_preview/print_preview.js
+++ b/chrome/browser/resources/print_preview/print_preview.js
@@ -285,7 +285,10 @@ cr.define('print_preview', function() {
           this.nativeLayer_,
           print_preview.NativeLayer.EventType.PRIVET_PRINT_FAILED,
           this.onPrivetPrintFailed_.bind(this));
-
+      this.tracker.add(
+          this.nativeLayer_,
+          print_preview.NativeLayer.EventType.MANIPULATE_SETTINGS_FOR_TEST,
+          this.onManipulateSettingsForTest_.bind(this));
 
       this.tracker.add(
           $('system-dialog-link'),
@@ -691,6 +694,7 @@ cr.define('print_preview', function() {
     onPreviewGenerationDone_: function() {
       this.isPreviewGenerationInProgress_ = false;
       this.printHeader_.isPrintButtonEnabled = true;
+      this.nativeLayer_.previewReadyForTest();
       this.printIfReady_();
     },
 
@@ -890,6 +894,70 @@ cr.define('print_preview', function() {
     },
 
     /**
+     * Called when the print preview settings need to be changed for testing.
+     * @param {Event} event Event object that contains the option that is to
+     *     be changed and what to set that option.
+     * @private
+     */
+    onManipulateSettingsForTest_: function(event) {
+      if ('selectSaveAsPdfDestination' in event.settings) {
+        var destinations = this.destinationStore_.destinations();
+        var pdfDestination = null;
+        for (var i = 0; i < destinations.length; i++) {
+          if (destinations[i].id ==
+              print_preview.Destination.GooglePromotedId.SAVE_AS_PDF) {
+            pdfDestination = destinations[i];
+            break;
+          }
+        }
+        if (pdfDestination)
+          this.destinationStore_.selectDestination(pdfDestination);
+        else
+          this.nativeLayer_.previewFailedForTest();
+      } else if ('layoutSettings' in event.settings) {
+        var element = document.querySelector(
+            event.settings.layoutSettings.portrait ?
+                '.layout-settings-portrait-radio' :
+                '.layout-settings-landscape-radio');
+        if (element.clicked)
+          this.nativeLayer_.previewReadyForTest();
+        else
+          element.click();
+      } else if ('pageRange' in event.settings) {
+        var textbox = document.querySelector('.page-settings-custom-input');
+        if (textbox.value == event.settings.pageRange) {
+          this.nativeLayer_.previewReadyForTest();
+        } else {
+          textbox.value = event.settings.pageRange;
+          document.querySelector('.page-settings-custom-radio').click();
+        }
+      } else if ('headersAndFooters' in event.settings) {
+        var checkbox = document.querySelector('.header-footer-checkbox');
+        if (event.settings.headersAndFooters == checkbox.checked)
+          this.nativeLayer_.previewReadyForTest();
+        else
+          checkbox.click();
+      } else if ('backgroundColorsAndImages' in event.settings) {
+        var checkbox = document.querySelector('.css-background-checkbox');
+        if (event.settings.backgroundColorsAndImages == checkbox.checked)
+          this.nativeLayer_.previewReadyForTest();
+        else
+          checkbox.click();
+      } else if ('margins' in event.settings) {
+        var combobox = document.querySelector('.margin-settings-select');
+        if (event.settings.margins == combobox.selectedIndex) {
+          this.nativeLayer_.previewReadyForTest();
+        } else if (event.settings.margins >= 0 &&
+                   event.settings.margins < combobox.length) {
+          combobox.selectedIndex = event.settings.margins;
+          this.marginSettings_.onSelectChange_();
+        } else {
+          this.nativeLayer_.previewFailedForTest();
+        }
+      }
+    },

[Dan Beam, 2014/06/24 23:13:01]

"much code, no newlines, ow" - my eyes

[ivandavid, 2014/06/25 00:02:22]

Ha. I am not sure where to put new lines though. I tried putting them in, but it
made the code look awkward. This whole file looks like this and Aleksey said the
one nice place where some newlines would be good are before the 'else if'
statements. Any suggestions for where I should put some newlines?

[ivandavid, 2014/06/25 00:04:08]

And those new lines don't conform to the style guide.

+
+    /**
      * Called when the open-cloud-print-dialog link is clicked. Opens the Google
      * Cloud Print web dialog.
      * @private