platform-window: Add a PlatformWindowFactory for creating windows.

ui/platform_window/x11/x11_window_factory.cc

+// Copyright 2014 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/platform_window/x11/x11_window_factory.h"
+
+#include "ui/events/platform/platform_event_source.h"
+#include "ui/platform_window/x11/x11_window.h"
+
+namespace ui {
+
+X11WindowFactory::X11WindowFactory()
+    : event_source_(ui::PlatformEventSource::CreateDefault()) {
+}
+
+X11WindowFactory::~X11WindowFactory() {
+}
+
+// static
+PlatformWindowFactory* X11WindowFactory::CreateIfNecessary() {
+  PlatformWindowFactory* instance = GetInstance();
+  if (!instance)
+    new X11WindowFactory();
+  instance = GetInstance();
+  CHECK(instance);
+  return instance;
+}
+
+scoped_ptr<PlatformWindow> X11WindowFactory::CreatePlatformWindow(
+    PlatformWindowDelegate* delegate,
+    const gfx::Rect& bounds) {
+  scoped_ptr<PlatformWindow> window(new X11Window(delegate));
+  window->SetBounds(bounds);
+  return window.Pass();
+}
+
+}  // namespace ui