Print preview not showing if default print is invalid.

chrome/renderer/print_web_view_helper.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/print_web_view_helper.h"
 
 #if defined(OS_MACOSX) && !defined(USE_SKIA)
 #include <CoreGraphics/CGContext.h>
 #endif
 
@@ skipping 611 matching lines @@
     WebNode duplicate_node(*node);
     Print(frame, &duplicate_node);
   }
 }
 
 void PrintWebViewHelper::OnPrintPreview(const DictionaryValue& settings) {
   DCHECK(is_preview_);
   print_preview_context_.OnPrintPreview();
 
   if (!InitPrintSettings(print_preview_context_.frame(),
-                         print_preview_context_.node())) {
-    NOTREACHED();
+                         print_preview_context_.node(),
+                         true)) {
+    Send(new PrintHostMsg_PrintPreviewInvalidDefaultPrinter(
+                 routing_id(),
+                 print_pages_params_->params.document_cookie));
     return;
   }
 
   if (!UpdatePrintSettings(settings, true)) {
     DidFinishPrinting(FAIL_PREVIEW);
     return;
   }
 
   if (!print_pages_params_->params.is_first_request &&
       old_print_pages_params_.get() &&
@@ skipping 358 matching lines @@
       static_cast<int>(ConvertUnitDouble(
           page_height_in_points, printing::kPointsPerInch, dpi)));
 
   params->margin_top = static_cast<int>(ConvertUnitDouble(
       page_layout_in_points.margin_top, printing::kPointsPerInch, dpi));
   params->margin_left = static_cast<int>(ConvertUnitDouble(
       page_layout_in_points.margin_left, printing::kPointsPerInch, dpi));
 }
 
 bool PrintWebViewHelper::InitPrintSettings(WebKit::WebFrame* frame,
-                                           WebKit::WebNode* node) {
+                                           WebKit::WebNode* node,
+                                           bool is_preview) {
   DCHECK(frame);
   PrintMsg_PrintPages_Params settings;
 
   Send(new PrintHostMsg_GetDefaultPrintSettings(routing_id(),
                                                 &settings.params));
   // Check if the printer returned any settings, if the settings is empty, we
   // can safely assume there are no printer drivers configured. So we safely
   // terminate.
   if (PrintMsg_Print_Params_IsEmpty(settings.params)) {
-    render_view()->runModalAlertDialog(
-        frame,
-        l10n_util::GetStringUTF16(IDS_DEFAULT_PRINTER_NOT_FOUND_WARNING));
+    if (!is_preview) {
+      render_view()->runModalAlertDialog(
+          frame,
+          l10n_util::GetStringUTF16(IDS_DEFAULT_PRINTER_NOT_FOUND_WARNING));
+    }
     return false;
   }
   if (settings.params.dpi < kMinDpi || settings.params.document_cookie == 0) {
     // Invalid print page settings.
     NOTREACHED();
     return false;
   }
 
   settings.pages.clear();
   print_pages_params_.reset(new PrintMsg_PrintPages_Params(settings));
   return true;
 }
 
 bool PrintWebViewHelper::InitPrintSettingsAndPrepareFrame(
     WebKit::WebFrame* frame, WebKit::WebNode* node,
     scoped_ptr<PrepareFrameAndViewForPrint>* prepare) {
-  if (!InitPrintSettings(frame, node))
+  if (!InitPrintSettings(frame, node, false))
     return false;
 
   DCHECK(!prepare->get());
   prepare->reset(new PrepareFrameAndViewForPrint(print_pages_params_->params,
                                                  frame, node));
   UpdatePrintableSizeInPrintParameters(frame, node, prepare->get(),
                                        &print_pages_params_->params);
   Send(new PrintHostMsg_DidGetDocumentCookie(
         routing_id(), print_pages_params_->params.document_cookie));
   return true;
@@ skipping 385 matching lines @@
 const gfx::Size&
 PrintWebViewHelper::PrintPreviewContext::GetPrintCanvasSize() const {
   return prep_frame_view_->GetPrintCanvasSize();
 }
 
 void PrintWebViewHelper::PrintPreviewContext::ClearContext() {
   prep_frame_view_.reset();
   metafile_.reset();
   pages_to_render_.clear();
 }