fuchsia: Stub ui/base/idle

Fuchsia is initially trying to get a headless build up and
running so idle detection is unnecessary.

Bug: 743296
Change-Id: I497f42d533e853ce397eeae3ced19a490742c0ee
Reviewed-on: https://chromium-review.googlesource.com/596505
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491450}

ui/base/BUILD.gn

@@ -379,6 +379,7 @@ component("base") {
     sources += [
       "clipboard/clipboard_fuchsia.cc",
       "clipboard/clipboard_fuchsia.h",
+      "idle/idle_fuchsia.cc",
       "resource/resource_bundle_fuchsia.cc",
     ]
   }

ui/base/idle/idle_fuchsia.cc

+// Copyright 2017 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 "ui/base/idle/idle.h"
+
+#include "base/logging.h"
+
+namespace ui {
+
+void CalculateIdleTime(IdleTimeCallback notify) {
+  // TODO(fuchsia): https://crbug.com/743296.
+  NOTIMPLEMENTED();
+  notify.Run(0);
+}
+
+bool CheckIdleStateIsLocked() {
+  // TODO(fuchsia): https://crbug.com/743296.
+  NOTIMPLEMENTED();
+  return false;
+}
+
+}  // namespace ui