Printing: Keep track of WebContents lifetime for the native printing UI.

chrome/browser/printing/printing_message_filter.cc

Index: chrome/browser/printing/printing_message_filter.cc
diff --git a/chrome/browser/printing/printing_message_filter.cc b/chrome/browser/printing/printing_message_filter.cc
index 79a11949918868e2ebce2dfef05ea61656d221f5..b338c02b7393833a0d98018c2df9bf929ef7efd4 100644
--- a/chrome/browser/printing/printing_message_filter.cc
+++ b/chrome/browser/printing/printing_message_filter.cc
@@ -10,13 +10,13 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/printing/printer_query.h"
 #include "chrome/browser/printing/print_job_manager.h"
+#include "chrome/browser/printing/printing_ui_web_contents_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/common/print_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
-#include "content/public/browser/web_contents_view.h"
 
 #if defined(ENABLE_FULL_PRINTING)
 #include "chrome/browser/ui/webui/print_preview/print_preview_ui.h"
@@ -273,10 +273,12 @@ void PrintingMessageFilter::GetPrintSettingsForRenderView(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   content::WebContents* wc = GetWebContentsForRenderView(render_view_id);
   if (wc) {
+    scoped_ptr<PrintingUIWebContentsObserver> wc_observer(
+        new PrintingUIWebContentsObserver(wc));
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(&printing::PrinterQuery::GetSettings, printer_query,
-                   params.ask_user_for_settings, wc->GetView()->GetNativeView(),
+                   params.ask_user_for_settings, base::Passed(&wc_observer),
                    params.expected_page_count, params.has_selection,
                    params.margin_type, callback));
   } else {