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

chrome/browser/resources/print_preview/print_preview.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // TODO(rltoscano): Move data/* into print_preview.data namespace
 
 var localStrings = new LocalStrings(templateData);
 
 <include src="component.js"/>
 
@@ skipping 267 matching lines @@
           print_preview.NativeLayer.EventType.SETTINGS_INVALID,
           this.onSettingsInvalid_.bind(this));
       this.tracker.add(
           this.nativeLayer_,
           print_preview.NativeLayer.EventType.DISABLE_SCALING,
           this.onDisableScaling_.bind(this));
       this.tracker.add(
           this.nativeLayer_,
           print_preview.NativeLayer.EventType.PRIVET_PRINT_FAILED,
           this.onPrivetPrintFailed_.bind(this));
-
+      this.tracker.add(
+          this.nativeLayer_,
+          print_preview.NativeLayer.EventType.MANIPULATE_SETTINGS,
+          this.onManipulateSettings_.bind(this));
 
       this.tracker.add(
           $('system-dialog-link'),
           'click',
           this.openSystemPrintDialog_.bind(this));
       this.tracker.add(
           $('cloud-print-dialog-link'),
           'click',
           this.onCloudPrintDialogLinkClick_.bind(this));
       this.tracker.add(
@@ skipping 385 matching lines @@
       this.isPreviewGenerationInProgress_ = true;
     },
 
     /**
      * Called when the preview area's preview generation is complete.
      * @private
      */
     onPreviewGenerationDone_: function() {
       this.isPreviewGenerationInProgress_ = false;
       this.printHeader_.isPrintButtonEnabled = true;
+      chrome.send('UILoaded');

[Lei Zhang, 2014/06/17 21:57:33]

You may want to rename "UiLoaded" to "UiLoadedForTest". Since it's not normally
needed.

[ivandavid, 2014/06/17 22:59:16]

Done.

       this.printIfReady_();
     },
 
     /**
      * Called when the preview area's preview failed to load.
      * @private
      */
     onPreviewGenerationFail_: function() {
       this.isPreviewGenerationInProgress_ = false;
       this.printHeader_.isPrintButtonEnabled = false;
@@ skipping 178 matching lines @@
      * @param {Event} event Event object representing the failure.
      * @private
      */
     onPrivetPrintFailed_: function(event) {
       console.error('Privet printing failed with error code ' +
                     event.httpError);
       this.printHeader_.setErrorMessage(
         localStrings.getString('couldNotPrint'));
     },
 
+    onManipulateSettings_: function(event) {
+      if (event.messageName == 'SAVE_AS_PDF') {
+        this.destinationStore_.selectDefaultDestination_();
+      }
+      else if (event.messageName == 'LAYOUT_SETTINGS') {
+        if (event.layoutSettings == 'LANDSCAPE') {
+          var landscape = document.getElementsByClassName(
+            'layout-settings-landscape-radio')[0];
+          if (landscape) {
+            landscape.click();
+          }
+        } else {
+          chrome.send('UILoaded');

[Lei Zhang, 2014/06/17 21:57:33]

Why not click the portrait button in this case? That is, go with the regular
workflow and naturally send a UILoaded event, rather than having to remember to
do it here again.

[ivandavid, 2014/06/17 22:59:16]

I didn't think it would work because its already selected by default. However, I
implemented your change and it worked.

+        }
+      }
+      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 {
+          chrome.send('UILoaded');
+        }
+      }
+      else if (event.messageName == 'HEADERS_AND_FOOTERS') {
+        if (event.headersAndFooters == false) {
+          var headerFooterCheckbox = document.getElementsByClassName(
+              'header-footer-checkbox');
+          if (headerFooterCheckbox) {
+            this.otherOptionsSettings_.headerFooterCheckbox_.click();
+          }
+        } else {
+          chrome.send('UILoaded');
+        }
+      }
+      else if (event.messageName == 'BACKGROUND_COLORS_AND_IMAGES') {
+        if (event.backgroundColorsAndImages == true) {
+          var backgroundCheckbox = document.getElementsByClassName(
+              'css-background-checkbox')[0];
+          if (backgroundCheckbox) {
+            this.otherOptionsSettings_.cssBackgroundCheckbox_.click();
+          }
+        } else {
+          chrome.send('UILoaded');
+        }
+      }
+      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;
+           chrome.send('UILoaded');
+        } else {
+          chrome.send('UILoaded');
+        }
+      }
+    },
+
     /**
      * Called when the open-cloud-print-dialog link is clicked. Opens the Google
      * Cloud Print web dialog.
      * @private
      */
     onCloudPrintDialogLinkClick_: function() {
       assert(this.uiState_ == PrintPreview.UiState_.READY,
              'Opening Google Cloud Print dialog when not in ready state: ' +
                  this.uiState_);
       setIsVisible($('cloud-print-dialog-throbber'), true);
@@ skipping 132 matching lines @@
 <include src="search/recent_destination_list.js"/>
 <include src="search/destination_list_item.js"/>
 <include src="search/destination_search.js"/>
 <include src="search/search_box.js"/>
 <include src="search/fedex_tos.js"/>
 
 window.addEventListener('DOMContentLoaded', function() {
   printPreview = new print_preview.PrintPreview();
   printPreview.initialize();
 });