Send request to show print system dialog to Metro.

printing/printing_context_win.cc

 // Copyright (c) 2012 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 "printing/printing_context_win.h"
 
 #include <winspool.h>
 
 #include <algorithm>
 
 #include "base/i18n/file_util_icu.h"
 #include "base/i18n/time_formatting.h"
 #include "base/message_loop.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
+#include "base/win/metro.h"
 #include "printing/backend/win_helper.h"
 #include "printing/print_job_constants.h"
 #include "printing/print_settings_initializer_win.h"
 #include "printing/printed_document.h"
 #include "printing/units.h"
 #include "skia/ext/platform_device.h"
 
 using base::Time;
 
 namespace {
@@ skipping 185 matching lines @@
 
 PrintingContextWin::~PrintingContextWin() {
   ReleaseContext();
 }
 
 void PrintingContextWin::AskUserForSettings(
     gfx::NativeView view, int max_pages, bool has_selection,
     const PrintSettingsCallback& callback) {
 #if !defined(USE_AURA)
   DCHECK(!in_print_job_);
+
+  if (base::win::IsMetroProcess()) {
+    // The system dialog can not be opened while running in Metro.
+    // But we can programatically launch the Metro print device charm though.
+    HMODULE metro_module = base::win::GetMetroModule();
+    if (metro_module != NULL) {
+      typedef void (*MetroShowPrintUI)();

[Albert Bodenhamer, 2012/07/12 16:32:10]

Nit: Is the prototype for MetroShowPrintUI defined in a header somewhere?

Longer term: Does it make sense to build a wrapper class around the the Metro
module that will either delay load or dynamically load the DLL and fail
gracefully?  Exposing all of the dynamic load code in callers adds clutter and
bloat.

[MAD, 2012/07/12 17:16:14]

There's work in progress for this... Not quite ready yet...

+      MetroShowPrintUI metro_show_print_ui =
+          reinterpret_cast<MetroShowPrintUI>(
+              ::GetProcAddress(metro_module, "MetroShowPrintUI"));
+      if (metro_show_print_ui)
+        metro_show_print_ui();
+    }
+    return callback.Run(CANCEL);
+  }
   dialog_box_dismissed_ = false;
 
   HWND window;
   if (!view || !IsWindow(view)) {
     // TODO(maruel):  bug 1214347 Get the right browser window instead.
     window = GetDesktopWindow();
   } else {
     window = GetAncestor(view, GA_ROOTOWNER);
   }
   DCHECK(window);
@@ skipping 565 matching lines @@
   if (buf_size) {
     buffer->reset(new uint8[buf_size]);
     memset(buffer->get(), 0, buf_size);
     if (!GetPrinter(printer, level, buffer->get(), buf_size, &buf_size)) {
       buffer->reset();
     }
   }
 }
 
 }  // namespace printing