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..559eda17ea0ff57afcbe78d3b641dafbc1e89c6d 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 +694,9 @@ cr.define('print_preview', function() {
     onPreviewGenerationDone_: function() {
       this.isPreviewGenerationInProgress_ = false;
       this.printHeader_.isPrintButtonEnabled = true;
+      if (global['onManipulateSettingsForTest']) {
+        this.nativeLayer_.doneManipulatingSettings();
+      }
       this.printIfReady_();
     },
 
@@ -889,6 +895,99 @@ cr.define('print_preview', function() {
         localStrings.getString('couldNotPrint'));
     },
 
+    onManipulateSettingsForTest_: function(event) {
+      if (event.messageName == 'SAVE_AS_PDF') {
+        this.destinationStore_.selectDefaultDestination_();
+      }
+      else if (event.messageName == 'LAYOUT_SETTINGS') {
+        if (event.isPortrait == true) {
+          var portrait = document.getElementsByClassName(
+            'layout-settings-portrait-radio')[0];
+          if (portrait) {
+            portrait.click();
+          } else {
+            this.nativeLayer_.doneManipulatingSettings();
+          }
+        } else {
+          var landscape = document.getElementsByClassName(
+            'layout-settings-landscape-radio')[0];
+          if (landscape) {
+            landscape.click();
+          } else {

[ivandavid, 2014/06/18 00:26:00]

I think this handles this situation. I will have to find a way to test this.

[Lei Zhang, 2014/06/18 00:47:58]

The entire layout settings block here can be simplified a little:

var elementName = event.isPortrait ?
    'layout-settings-portrait-radio' : 'layout-settings-landscape-radio';
var element = document.getElementsByClassName(elementName)[0];
if ...

+            this.nativeLayer_.doneManipulatingSettings();
+          }
+        }
+      }
+      else if (event.messageName == 'PAGE_NUMBERS') {
+        if (event.pageNumbers != '') {
+          var pageSettingsCustomInput = document.getElementsByClassName(
+              'page-settings-custom-input')[0];
+          if (pageSettingsCustomInput) {
+            pageSettingsCustomInput.value = event.pageSettings;
+          }
+        } else {
+          this.nativeLayer_.doneManipulatingSettings();
+        }
+      }
+      else if (event.messageName == 'HEADERS_AND_FOOTERS') {
+        if (event.headersAndFooters == false) {

[Lei Zhang, 2014/06/18 00:47:58]

The if and else cases here also have a lot of duplicate code.

+          var headerFooterCheckbox = document.getElementsByClassName(
+              'header-footer-checkbox')[0];
+          if (headerFooterCheckbox) {
+            if (headerFooterCheckbox.checked == true) {

[Lei Zhang, 2014/06/18 00:47:58]

In general, I think in JS you can just do: if (foo) ...

+              this.otherOptionsSettings_.headerFooterCheckbox_.click();
+            } else {
+              this.nativeLayer_.doneManipulatingSettings();
+            }
+          }
+        } else {
+          var headerFooterCheckbox = document.getElementsByClassName(
+              'header-footer-checkbox')[0];
+          if (headerFooterCheckbox) {
+            if (headerFooterCheckbox.checked == false) {
+              this.otherOptionsSettings_.headerFooterCheckbox_.click();
+            } else {
+              this.nativeLayer_.doneManipulatingSettings();
+            }
+          }
+        }
+      }
+      else if (event.messageName == 'BACKGROUND_COLORS_AND_IMAGES') {
+        if (event.backgroundColorsAndImages == true) {
+          var backgroundCheckbox = document.getElementsByClassName(
+              'css-background-checkbox')[0];
+          if (backgroundCheckbox) {
+            if (backgroundCheckbox.checked == false) {
+              this.otherOptionsSettings_.cssBackgroundCheckbox_.click();
+            } else {
+              this.nativeLayer_.doneManipulatingSettings();
+            }
+          }
+        } else {
+          var backgroundCheckbox = document.getElementsByClassName(
+              'css-background-checkbox')[0];
+          if (backgroundCheckbox) {
+            if (backgroundCheckbox.checked == true) {
+              this.otherOptionsSettings_.cssBackgroundCheckbox_.click();
+            } else {
+              this.nativeLayer_.doneManipulatingSettings();
+            }
+          }
+        }
+      }
+      else if (event.messageName == 'MARGINS') {
+        var marginSettingsSelect =
+            document.getElementsByClassName('margin-settings-select')[0];
+        var index = parseInt(event.margins, 10);
+        if (marginSettingsSelect && index != 0) {
+          marginSettingsSelect.selectedIndex = index;
+          this.marginSettings_.onSelectChange_();
+        } else {
+          this.nativeLayer_.doneManipulatingSettings();
+        }
+      }
+    },
+
     /**
      * Called when the open-cloud-print-dialog link is clicked. Opens the Google
      * Cloud Print web dialog.