Printing: Call PrintingContext::AskUserForSettings() on the UI thread for Linux

chrome/browser/printing/print_job_worker.h

Index: chrome/browser/printing/print_job_worker.h
diff --git a/chrome/browser/printing/print_job_worker.h b/chrome/browser/printing/print_job_worker.h
index f79ca862e688728bb6568338460037075c2accb1..69b35e42328d7cd51220202250fa2522181840d3 100644
--- a/chrome/browser/printing/print_job_worker.h
+++ b/chrome/browser/printing/print_job_worker.h
@@ -81,9 +81,9 @@ class PrintJobWorker : public base::Thread {
   // context.
   void OnFailure();
 
-#if defined(OS_MACOSX)
+#if defined(OS_MACOSX) || defined(USE_X11)
   // Asks the user for print settings. Must be called on the UI thread.
-  // Mac-only since Windows can display UI from non-main threads.
+  // Mac and Linux-only since Windows can display UI from non-main threads.
   void GetSettingsWithUI(gfx::NativeView parent_view,
                          int document_page_count,
                          bool has_selection);