platform-window: Add a PlatformWindowFactory for creating windows.

ui/platform_window/platform_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/platform_window_factory.h"
+
+#include "base/at_exit.h"
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/events/platform/platform_event_source.h"
+#include "ui/platform_window/types/platform_window.h"
+
+#if defined(USE_X11)
+#include "ui/platform_window/x11/x11_window.h"
+#elif defined(OS_WIN)
+#include "ui/platform_window/win/win_window.h"
+#elif defined(USE_OZONE)
+#include "ui/ozone/public/ozone_platform.h"
+#endif
+
+namespace ui {
+
+namespace {
+
+PlatformWindowFactory* instance = NULL;
+
+class DefaultPlatformWindowFactory : public PlatformWindowFactory {
+ public:
+  DefaultPlatformWindowFactory()
+      : event_source_(PlatformEventSource::CreateDefault()) {}
+  virtual ~DefaultPlatformWindowFactory() {}
+
+ private:
+  // PlatformWindowFactory:
+  virtual scoped_ptr<PlatformWindow> CreatePlatformWindow(
+      PlatformWindowDelegate* delegate,
+      const gfx::Rect& bounds) OVERRIDE {
+    scoped_ptr<PlatformWindow> window;
+#if defined(USE_X11)
+    window.reset(new X11Window(delegate));
+    window->SetBounds(bounds);
+#elif defined(OS_WIN)
+    window.reset(new WinWindow(delegate, bounds));
+#elif defined(USE_OZONE)
+    window =
+        OzonePlatform::GetInstance()->CreatePlatformWindow(delegate, bounds);
+#else
+    NOTREACHED();
+#endif
+    return window.Pass();
+  }
+
+  scoped_ptr<PlatformEventSource> event_source_;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultPlatformWindowFactory);
+};
+
+}  // namespace
+
+PlatformWindowFactory::PlatformWindowFactory() {
+  CHECK(!instance) << "There can only be a single PlatformWindowFactory.";
+  instance = this;
+  base::AtExitManager::RegisterTask(
+      base::Bind(&base::DeletePointer<PlatformWindowFactory>, instance));
+}
+
+PlatformWindowFactory::~PlatformWindowFactory() {
+  CHECK_EQ(instance, this);
+  instance = NULL;
+}
+
+// static
+PlatformWindowFactory* PlatformWindowFactory::GetInstance() {
+  if (!instance)
+    new DefaultPlatformWindowFactory();
+  CHECK(instance);
+  return instance;
+}
+
+}  // namespace ui