Start consolidating cross-port file selection code into ui/base/dialogs.

chrome/browser/chrome_select_file_policy.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 "chrome/browser/chrome_select_file_policy.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/logging.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/infobars/infobar_tab_helper.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/tab_contents/simple_alert_infobar_delegate.h"
+#include "chrome/browser/ui/tab_contents/tab_contents.h"
+#include "chrome/common/pref_names.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+
+ChromeSelectFilePolicy::ChromeSelectFilePolicy() {}
+
+ChromeSelectFilePolicy::~ChromeSelectFilePolicy() {}
+
+bool ChromeSelectFilePolicy::CanOpenSelectFileDialog() {
+  DCHECK(g_browser_process);
+
+  // local_state() can return NULL for tests.
+  if (!g_browser_process->local_state())
+    return false;
+
+  return !g_browser_process->local_state()->FindPreference(
+             prefs::kAllowFileSelectionDialogs) ||
+         g_browser_process->local_state()->GetBoolean(
+             prefs::kAllowFileSelectionDialogs);
+}
+
+// static
+base::Closure ChromeSelectFilePolicy::DisplayInfobarCallback(
+    content::WebContents* source_contents) {
+  return base::Bind(&DisplayInfobarOrWarn, base::Unretained(source_contents));
+}
+
+// static
+void ChromeSelectFilePolicy::DisplayInfobarOrWarn(
+    content::WebContents* source_contents) {
+  // Show the InfoBar saying that file-selection dialogs are disabled.
+  if (source_contents) {
+    TabContents* tab_contents = TabContents::FromWebContents(source_contents);

[sky, 2012/06/26 00:07:18]

Can't this return NULL?

[Elliot Glaysher, 2012/06/28 20:09:53]

It can return NULL only if |source_contents| is invalid. This usage is OK
because the Closure isn't stored and is used down stack of where we have to have
a valid WebContents.

Still, I've added a DCHECK().

+    InfoBarTabHelper* infobar_helper = tab_contents->infobar_tab_helper();
+    infobar_helper->AddInfoBar(new SimpleAlertInfoBarDelegate(
+        infobar_helper,
+        NULL,
+        l10n_util::GetStringUTF16(IDS_FILE_SELECTION_DIALOG_INFOBAR),
+        true));
+  } else {
+    LOG(WARNING) << "File-selection dialogs are disabled but no WebContents "
+                 << "is given to display the InfoBar.";
+  }
+}