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..28219eff25a6052589e36c7d1ee6f05fe56875ee 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 +894,95 @@ 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 didSet = false;
+        for (var i = 0; i < destinations.length; i++) {
+          if (destinations[i].id == print_preview.Destination.GooglePromotedId.
+              SAVE_AS_PDF) {
+            this.destinationStore_.selectDestination(destinations[i]);
+            didSet = true;
+            break;
+          }
+        }
+        if (!didSet)
+          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) {
+          if (element.clicked)
+            this.nativeLayer_.previewReadyForTest();
+          else
+            element.click();
+        } else
+          this.nativeLayer_.previewFailedForTest();
+
+      } else if ('pageRange' in event.settings) {
+        var textbox = document.querySelector('.page-settings-custom-input');
+        if (textbox) {
+          if (textbox.value == event.settings.pageRange)
+            this.nativeLayer_.previewReadyForTest();
+          else {
+            // Assuming that the string format is correct for now.
+            // TODO: Will need a way to validate it just so the test doesn't
+            //    hang mysteriously if the string isn't correct.
+            textbox.value = event.settings.pageRange;
+
+            // Triggers the re-rendering of the preview area as
+            // just setting the value isn't sufficient.
+            var radio = document.querySelector('.page-settings-custom-radio');
+            if (radio)
+              radio.click();
+            else
+              this.nativeLayer_.previewFailedForTest();
+          }
+        } else
+          this.nativeLayer_.previewFailedForTest();
+      } else if ('headersAndFooters' in event.settings) {
+        var checkbox = document.querySelector(
+            '.header-footer-checkbox');
+        if (checkbox) {
+          if (event.settings.headersAndFooters == checkbox.checked)
+            this.nativeLayer_.previewReadyForTest();
+          else
+            checkbox.click();
+        } else
+          this.nativeLayer_.previewFailedForTest();
+      } else if ('backgroundColorsAndImages' in event.settings) {
+        var checkbox = document.querySelector('.css-background-checkbox');
+        if (checkbox) {
+          if (event.settings.backgroundColorsAndImages == checkbox.checked)
+            this.nativeLayer_.previewReadyForTest();
+          else
+            checkbox.click();
+        } else
+          this.nativeLayer_.previewFailedForTest();
+      } else if ('margins' in event.settings) {
+        var element = document.querySelector('.margin-settings-select');
+        if (element) {
+          if (event.settings.margins == element.selectedIndex)
+            this.nativeLayer_.previewReadyForTest();
+          else if (event.settings.margins >= 0 &&
+                     event.settings.margins < element.length) {
+            element.selectedIndex = event.settings.margins;
+            this.marginSettings_.onSelectChange_();
+          } else
+            this.nativeLayer_.previewFailedForTest();
+        } else
+          this.nativeLayer_.previewFailedForTest();
+      }
+    },
+
+    /**
      * Called when the open-cloud-print-dialog link is clicked. Opens the Google
      * Cloud Print web dialog.
      * @private