Use BaseShellDialog for print dialog on Windows

ui/shell_dialogs/print_settings_dialog_win.h

+// Copyright 2013 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.
+
+#ifndef UI_SHELL_DIALOGS_PRINT_SETTINGS_DIALOG_WIN_H_
+#define UI_SHELL_DIALOGS_PRINT_SETTINGS_DIALOG_WIN_H_
+
+#include <ocidl.h>
+#include <commdlg.h>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "ui/shell_dialogs/base_shell_dialog_win.h"
+#include "ui/shell_dialogs/shell_dialogs_export.h"
+
+namespace ui {
+
+// A thin wrapper around the native window print dialog that uses
+// BaseShellDialog to have the dialog run on a background thread.
+class SHELL_DIALOGS_EXPORT PrintSettingsDialogWin
+    : public base::RefCountedThreadSafe<PrintSettingsDialogWin>,
+      public BaseShellDialogImpl {
+ public:
+  class SHELL_DIALOGS_EXPORT Observer {
+   public:
+    virtual void PrintSettingsConfirmed(PRINTDLGEX* dialog_options) = 0;
+    virtual void PrintSettingsCancelled(PRINTDLGEX* dialog_options) = 0;
+  };
+  typedef HRESULT(__stdcall* PrintDialogFunc)(PRINTDLGEX*);
+
+  explicit PrintSettingsDialogWin(Observer* observer);
+  virtual ~PrintSettingsDialogWin();
+
+  // Called to open the system print dialog on a background thread.
+  // |print_dialog_func| should generally be ::PrintDlgEx, however alternate
+  // functions are used for testing. |owning_window| is the parent HWND, and
+  // |dialog_options| is passed to |print_dialog_func|.
+  void GetPrintSettings(
+      PrintDialogFunc print_dialog_func,
+      HWND owning_window,
+      PRINTDLGEX* dialog_options);
+
+ private:
+  // A struct for holding all the state necessary for displaying the print
+  // settings dialog.
+  struct ExecutePrintSettingsParams {
+    ExecutePrintSettingsParams(RunState run_state,
+                               HWND owner,
+                               PrintDialogFunc print_dialog_func,
+                               PRINTDLGEX* dialog_options)
+        : run_state(run_state),
+          owner(owner),
+          print_dialog_func(print_dialog_func),
+          dialog_options(dialog_options),
+          ui_proxy(base::MessageLoopForUI::current()->message_loop_proxy()) {}
+
+    RunState run_state;
+    HWND owner;
+    PrintDialogFunc print_dialog_func;
+    PRINTDLGEX* dialog_options;
+    scoped_refptr<base::MessageLoopProxy> ui_proxy;
+  };
+
+  // Runs the print dialog. Should be run on the the BaseShellDialogImpl thread.
+  // Posts back to PrintSettingsCompleted on the UI thread on completion.
+  void ExecutePrintSettings(const ExecutePrintSettingsParams& params);
+
+  // Handler for the result of the print settings dialog. Should be run on the
+  // UI thread, and notifies the observer of the result of the dialog.
+  void PrintSettingsCompleted(HRESULT hresult,
+                              const ExecutePrintSettingsParams& params);
+
+  // Observer that's notified when the dialog is confirmed or cancelled.
+  Observer* observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintSettingsDialogWin);
+};
+
+}  // namespace ui
+
+#endif  // UI_SHELL_DIALOGS_PRINT_SETTINGS_DIALOG_WIN_H_