Extract locking behaviour from ProcessSingleton.

chrome/browser/modal_dialog_lock.cc

Index: chrome/browser/modal_dialog_lock.cc
diff --git a/chrome/browser/modal_dialog_lock.cc b/chrome/browser/modal_dialog_lock.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c341fee96428b25454dfd79fda18cf8e579c9560
--- /dev/null
+++ b/chrome/browser/modal_dialog_lock.cc
@@ -0,0 +1,54 @@
+// 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/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"
+
+ModalDialogLock::ModalDialogLock(
+    const ProcessSingleton::NotificationCallback& original_callback)
+    : active_dialog_(NULL),
+      original_callback_(original_callback) {}
+
+ModalDialogLock::~ModalDialogLock() {}
+
+void ModalDialogLock::SetActiveModalDialog(gfx::NativeWindow active_dialog) {
+#if !defined(OS_WIN) || defined(USE_AURA)

[gab, 2013/03/27 18:03:26]

If this is only meant to be used on Windows, why not make this entire class
_win.cc?

[gab, 2013/03/27 18:03:26]

Why is this a NOTREACHED() on win-Aura?

[erikwright (departed), 2013/03/28 03:16:34]

I didn't want to force too may #ifdef's in the client code. In any case, it's
much less win-specific now, although it would fail if actually used because the
platform-specific SetForegroundWindow is not supplied yet.

[erikwright (departed), 2013/03/28 03:16:34]

It was never actually called and eventually we would fail because we don't have
a SetForegroundWindow equivalent. But I've reworked the failure mode a bit.

+    NOTREACHED();

[gab, 2013/03/27 18:03:26]

nit: indent two less spaces.

[erikwright (departed), 2013/03/28 03:16:34]

n/a.

+#else
+  active_dialog_ = active_dialog;
+#endif
+}
+
+ProcessSingleton::NotificationCallback
+ModalDialogLock::AsNotificationCallback() {
+#if !defined(OS_WIN) || defined(USE_AURA)
+  return original_callback_;
+#else
+  return base::Bind(&ModalDialogLock::NotificationCallbackImpl,
+                    base::Unretained(this));
+#endif
+}
+
+bool ModalDialogLock::NotificationCallbackImpl(
+      const CommandLine& command_line,
+      const base::FilePath& current_directory) {
+  if (active_dialog_ != NULL) {
+#if !defined(OS_WIN) || defined(USE_AURA)
+    NOTREACHED();
+#else
+    ::SetForegroundWindow(active_dialog_);
+#endif
+    return true;
+  } else {
+    return original_callback_.Run(command_line, current_directory);
+  }
+}