Add note page to settings.

chrome/browser/ui/webui/settings/chromeos/note_handler.cc

+// Copyright 2016 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/ui/webui/settings/chromeos/note_handler.h"
+
+#include "ash/common/ash_switches.h"
+#include "base/command_line.h"
+#include "content/public/browser/web_ui_data_source.h"
+
+namespace chromeos {
+namespace settings {
+
+namespace {
+
+bool IsPaletteEnabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      ash::switches::kAshEnablePalette);
+}
+
+}  // namespace
+
+NoteHandler::NoteHandler(content::WebUIDataSource* html_source) {

[jdufault, 2016/07/26 19:42:56]

For right now, the handler is very simple, so it is reasonable to remove it
entirely and inline this code into md_settings_ui.cc.

However, in the future there will be additional settings in this page to select
the default note-taking application. This will require adding a message handler
here, so I figured I'd implement the boilerplate now rather than later to reduce
unnecessary churn.

[stevenjb, 2016/07/26 23:21:39]

Ideally we will use an extension API instead of a message handler, let's omit
this until / unless we need it.

[jdufault, 2016/07/27 20:55:02]

Most settings UI appears to use an message handler - is there any reason why
this necessitates an extension API? The extension API would have one method,
getAppIdsSupportingAction(DOMString actionId), or something like that.

[stevenjb, 2016/07/27 22:29:42]

Some day, we would like to be able to run device specific settings from the
login screen or from a kiosk app. Ideally Settings would be run as a stand-alone
app with no associated Chrome instance, i.e. AppShell. In that environment we
would need to rely on extension APIs that exist in AppShell.

We're a ways from that being the case, so I wouldn't discard this code, but I
would still prefer to only add it when we actually need it. Priorities have a
habit of changing.

[jdufault, 2016/07/28 17:54:40]

Done.

+  html_source->AddBoolean("noteAllowed", IsPaletteEnabled());
+}
+
+NoteHandler::~NoteHandler() {}
+
+void NoteHandler::RegisterMessages() {}
+
+void NoteHandler::OnJavascriptAllowed() {}
+
+void NoteHandler::OnJavascriptDisallowed() {}
+
+}  // namespace settings
+}  // namespace chromeos