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..179f9233a9965a78d8e9449ed2fedd4e8ccbddc4 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.CLICK_STUFF,
+          this.onClickStuff_.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;
+      chrome.send('UILoaded');
       this.printIfReady_();
     },
 
@@ -889,6 +893,16 @@ cr.define('print_preview', function() {
         localStrings.getString('couldNotPrint'));
     },
 
+    onClickStuff_: function() {

[Lei Zhang, 2014/06/16 23:12:40]

Are you going to expand this function to have parameters, so its action is not
hard coded to do just one thing, or are you going to have multiple functions to
take different actions?

[ivandavid, 2014/06/17 00:38:56]

I am going to expand this function to take arguments.

[Lei Zhang, 2014/06/17 00:53:26]

If you can continue working on this CL and do this, that would be great.

[ivandavid, 2014/06/17 21:38:18]

Done.

+      var settings = $('layout-settings');
+      this.destinationStore_.selectDefaultDestination_();
+      var portrait = document.getElementsByClassName(
+          'layout-settings-landscape-radio')[0];
+      if (portrait) {
+        portrait.click();
+      }
+    },
+
     /**
      * Called when the open-cloud-print-dialog link is clicked. Opens the Google
      * Cloud Print web dialog.