Minimize headless code that refers to aura.

headless/lib/browser/headless_browser_impl_aura.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 "content/public/browser/render_widget_host_view.h"
+#include "content/public/browser/web_contents.h"
+#include "headless/lib/browser/headless_browser_impl.h"
+#include "headless/lib/browser/headless_screen.h"
+#include "ui/aura/env.h"
+#include "ui/aura/window.h"
+#include "ui/display/screen.h"
+#include "ui/events/devices/device_data_manager.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace headless {
+
+void HeadlessBrowserImpl::PlatformInitialize() {
+  HeadlessScreen* screen = HeadlessScreen::Create(options()->window_size);
+  display::Screen::SetScreenInstance(screen);
+}
+
+void HeadlessBrowserImpl::PlatformCreateWindow() {
+  DCHECK(aura::Env::GetInstance());
+  ui::DeviceDataManager::CreateInstance();
+
+  window_tree_host_.reset(
+      new HeadlessWindowTreeHost(gfx::Rect(options()->window_size)));
+  window_tree_host_->InitHost();
+  window_tree_host_->NativeWindow()->Show();
+  window_tree_host_->SetParentWindow(window_tree_host_->NativeWindow());
+}
+
+void HeadlessBrowserImpl::PlatformSetContents(
+    const gfx::Size& initial_size,
+    content::WebContents* web_contents) {
+  gfx::NativeView contents = web_contents->GetNativeView();
+  gfx::NativeWindow parent_window = window_tree_host_->window();
+  DCHECK(!parent_window->Contains(contents));
+  parent_window->AddChild(contents);
+  contents->Show();
+  contents->SetBounds(gfx::Rect(initial_size));
+
+  content::RenderWidgetHostView* host_view =
+      web_contents->GetRenderWidgetHostView();
+  if (host_view)
+    host_view->SetSize(initial_size);
+}
+
+}  // namespace headless