Extract locking behaviour from ProcessSingleton.

chrome/browser/process_singleton_modal_dialog_lock.cc

+// Copyright (c) 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.
+
+#include "chrome/browser/process_singleton_modal_dialog_lock.h"
+
+#if defined(OS_WIN)
+#include <Windows.h>
+#endif
+
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+
+namespace {
+
+#if !defined(OS_WIN) || defined(USE_AURA)
+void DoSetForegroundWindow(gfx::NativeWindow /* target_window */) {
+  NOTREACHED();
+}
+#else
+void DoSetForegroundWindow(HWND target_window) {
+  ::SetForegroundWindow(target_window);
+}
+#endif
+
+}  // namespace
+
+ProcessSingletonModalDialogLock::ProcessSingletonModalDialogLock(
+    const ProcessSingleton::NotificationCallback& original_callback)
+    : active_dialog_(NULL),
+      original_callback_(original_callback),
+      set_foreground_window_handler_(base::Bind(&DoSetForegroundWindow)) {}
+
+ProcessSingletonModalDialogLock::ProcessSingletonModalDialogLock(
+    const ProcessSingleton::NotificationCallback& original_callback,
+    const SetForegroundWindowHandler& set_foreground_window_handler)
+    : active_dialog_(NULL),
+      original_callback_(original_callback),
+      set_foreground_window_handler_(set_foreground_window_handler) {}
+
+ProcessSingletonModalDialogLock::~ProcessSingletonModalDialogLock() {}
+
+void ProcessSingletonModalDialogLock::SetActiveModalDialog(
+    gfx::NativeWindow active_dialog) {
+  active_dialog_ = active_dialog;
+}
+
+ProcessSingleton::NotificationCallback
+ProcessSingletonModalDialogLock::AsNotificationCallback() {
+  return base::Bind(&ProcessSingletonModalDialogLock::NotificationCallbackImpl,
+                    base::Unretained(this));
+}
+
+bool ProcessSingletonModalDialogLock::NotificationCallbackImpl(
+      const CommandLine& command_line,
+      const base::FilePath& current_directory) {
+  if (active_dialog_ != NULL) {
+    set_foreground_window_handler_.Run(active_dialog_);
+    return true;
+  } else {
+    return original_callback_.Run(command_line, current_directory);
+  }
+}