Print preview not showing if default print is invalid.

chrome/renderer/mock_printer.h

Index: chrome/renderer/mock_printer.h
diff --git a/chrome/renderer/mock_printer.h b/chrome/renderer/mock_printer.h
index bbde2174000822557a53cac79c6790cc4787c9c0..b9d68469ee0e5c82a886451dc174ec49b15eb192 100644
--- a/chrome/renderer/mock_printer.h
+++ b/chrome/renderer/mock_printer.h
@@ -69,6 +69,7 @@ class MockPrinter {
   // Functions that changes settings of a pseudo printer.
   void ResetPrinter();
   void SetDefaultPrintSettings(const PrintMsg_Print_Params& params);
+  void UseInvalidSettings();
 
   // Functions that handles IPC events.
   void GetDefaultPrintSettings(PrintMsg_Print_Params* params);
@@ -142,6 +143,9 @@ class MockPrinter {
   string16 title_;
   string16 url_;
 
+  // Used for generating invalid settings.
+  bool use_invalid_settings_;
+
   std::vector<scoped_refptr<MockPrinterPage> > pages_;
 
   DISALLOW_COPY_AND_ASSIGN(MockPrinter);