Print Preview: Properly handle window.print().

chrome/renderer/print_web_view_helper.cc

Index: chrome/renderer/print_web_view_helper.cc
diff --git a/chrome/renderer/print_web_view_helper.cc b/chrome/renderer/print_web_view_helper.cc
index 1b4008a97bcaa5d503a430d14b999bc5e1d91754..638a178c93ac82caef2eabcc50bf36e93bb27844 100644
--- a/chrome/renderer/print_web_view_helper.cc
+++ b/chrome/renderer/print_web_view_helper.cc
@@ -462,7 +462,11 @@ void PrintWebViewHelper::PrintPage(WebKit::WebFrame* frame) {
 
   if (is_preview_enabled_) {
     print_preview_context_.InitWithFrame(frame);
-    RequestPrintPreview();
+
+    old_print_pages_params_.reset();  // Same as in RequestPrintPreview().
+    IPC::SyncMessage* msg = new PrintHostMsg_ScriptedPrintPreview(routing_id());
+    msg->EnableMessagePumping();
+    Send(msg);
   } else {
     Print(frame, WebNode());
   }