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..0809d7b9cd44429e8f9badf3ef9f33e54e28ebe6 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 +894,144 @@ 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) {
+        this.saveAsPdfForTest_(); // No parameters needed.

[ivandavid, 2014/07/03 03:12:03]

I split up this function and not native_layer.onManipulateSettingsForTest_().
This is because if I split that one up, I would have to add new event types to
native layer, and then I would have to send dispatch at least 6 different
different types of events.

+      } else if ('layoutSettings' in event.settings) {
+        this.setLayoutSettingsForTest_(event.settings.layoutSettings.portrait);
+      } else if ('pageRange' in event.settings) {
+        this.setPageRangeForTest_(event.settings.pageRange);
+      } else if ('headersAndFooters' in event.settings) {
+        this.setHeadersAndFootersForTest_(event.settings.headersAndFooters);
+      } else if ('backgroundColorsAndImages' in event.settings) {
+        this.setBackgroundColorsAndImagesForTest_(
+            event.settings.backgroundColorsAndImages);
+      } else if ('margins' in event.settings) {
+        this.setMarginsForTest_(event.settings.margins);
+      }
+    },
+
+    /**
+     * Called by onManipulateSettingsForTest_(). Sets the print destination
+     * as a pdf.
+     * @private
+     */
+    saveAsPdfForTest_: function() {
+      if (print_preview.Destination.GooglePromotedId.SAVE_AS_PDF ==
+            this.destinationStore_.selectedDestination.id) {
+        this.nativeLayer_.previewReadyForTest();
+        return;
+      }
+
+      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();

[Dan Beam, 2014/07/07 23:08:12]

indent off

[ivandavid, 2014/07/08 01:07:42]

Done.

+    },
+
+    /**
+     * Called by onManipulateSettingsForTest_(). Sets the layout settings to
+     * either portrait or landscape.
+     * @param {boolean} portrait If true then the portrait settings is to be

[Dan Beam, 2014/07/07 23:08:12]

nit: @param {boolean} portrait Whether to use portrait page layout; if false:
landscape.

[ivandavid, 2014/07/08 01:07:42]

Done.

+     *     set, otherwise, the landscape settings is set.
+     * @private
+     */
+    setLayoutSettingsForTest_: function(portrait) {
+      var element = document.querySelector(
+          portrait ?
+              '.layout-settings-portrait-radio' :
+              '.layout-settings-landscape-radio');
+      if (element.checked)
+        this.nativeLayer_.previewReadyForTest();
+      else
+          element.click();

[Dan Beam, 2014/07/07 23:08:12]

indent off

[ivandavid, 2014/07/08 01:07:42]

Done.

+    },
+
+    /**
+     * Called by onManipulateSettingsForTest_(). Sets the page range for
+     * for the print preview settings.
+     * @param {string} pageRange Sets the page range to the desired value(s).

[Dan Beam, 2014/07/07 23:08:12]

nit

* @param {string} pageRange A comma separated page range.  Ex: "1-5,9" 
*     means pages 1 through 5 and page 9.

[ivandavid, 2014/07/08 01:07:42]

Done.

+     *
+     * |pageRange| is a comma separated page range.
+     * Example: "1-5,9" will print pages 1 through 5 and page 9.
+     * The pages specified must be less than or equal to the maximum
+     * page number.
+     * @private
+     */
+    setPageRangeForTest_: function(pageRange) {
+      var textbox = document.querySelector('.page-settings-custom-input');
+      if (textbox.value == pageRange) {
+        this.nativeLayer_.previewReadyForTest();
+      } else {
+        textbox.value = pageRange;
+        document.querySelector('.page-settings-custom-radio').click();

[Dan Beam, 2014/07/07 23:08:12]

can you just do .click() event when the value's the same?

[ivandavid, 2014/07/08 01:07:42]

No, it doesn't cause the preview area to be generate again, therefore the test
hangs since the preview area has to be generated again for a message to be sent
to the test.

[Dan Beam, 2014/07/08 04:25:13]

ok

+      }
+    },
+
+    /**
+     * Called by onManipulateSettings_(). Checks or unchecks the headers and
+     * footers option on print preview.
+     * @param {boolean} headersAndFooters If true, the checkbox should be

[Dan Beam, 2014/07/07 23:08:12]

Whether the "Headers and footer" checkbox should be checked.

[ivandavid, 2014/07/08 01:07:42]

Done.

+     *     checked. Otherwise it should be unchecked.
+     * @private
+     */
+    setHeadersAndFootersForTest_: function(headersAndFooters) {
+      var checkbox = document.querySelector('.header-footer-checkbox');
+      if (headersAndFooters == checkbox.checked)
+        this.nativeLayer_.previewReadyForTest();
+      else
+        checkbox.click();
+    },
+
+    /**
+     * Called by onManipulateSettings_(). Checks or unchecks the background
+     * colors and images option on print preview.
+     * @param {boolean} backgroundColorsAndImages If true, the checkbox should
+     *     be checked. Otherwise it should be unchecked.
+     * @private
+     */
+    setBackgroundColorsAndImagesForTest_: function(backgroundColorsAndImages) {
+      var checkbox = document.querySelector('.css-background-checkbox');
+      if (backgroundColorsAndImages == checkbox.checked)
+        this.nativeLayer_.previewReadyForTest();
+      else
+        checkbox.click();
+    },
+
+    /**
+     * Called by onManipulateSettings_(). Sets the margin settings
+     * that are desired. Custom margin settings aren't currently supported.
+     * @param {number} margins The desired margins combobox index. Must be
+     *     a valid index or else the test fails.

[Dan Beam, 2014/07/07 23:08:12]

@private

[ivandavid, 2014/07/08 01:07:42]

Done.

+     */
+    setMarginsForTest_: function(margins) {
+      var combobox = document.querySelector('.margin-settings-select');
+      if (margins == combobox.selectedIndex) {
+        this.nativeLayer_.previewReadyForTest();
+      } else if (margins >= 0 && margins < combobox.length) {
+        combobox.selectedIndex = margins;
+        this.marginSettings_.onSelectChange_();
+      } else {
+        this.nativeLayer_.previewFailedForTest();
+      }
+    },
+
+    /**

[ivandavid, 2014/07/08 01:07:42]

Sorry for the double indents. I was writing python code previously and was
habitually hitting tab twice.

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