Demonstrate external-window-mode in mus-demo

services/ui/display/platform_screen_ozone.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 "services/ui/display/platform_screen_ozone.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "services/service_manager/public/cpp/interface_registry.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/display/types/display_constants.h"
 #include "ui/display/types/display_snapshot.h"
 #include "ui/display/types/native_display_delegate.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/ozone/public/ozone_platform.h"
+#include "ui/ozone/public/ozone_switches.h"
 
 namespace display {
 namespace {
 
 // Needed for DisplayConfigurator::ForceInitialConfigure.
 const SkColor kChromeOsBootColor = SkColorSetRGB(0xfe, 0xfe, 0xfe);
 
 const float kInchInMm = 25.4f;
 
 float ComputeDisplayDPI(const gfx::Size& pixel_size,
@@ skipping 44 matching lines @@
   std::unique_ptr<ui::NativeDisplayDelegate> native_display_delegate =
       ui::OzonePlatform::GetInstance()->CreateNativeDisplayDelegate();
 
   // The FakeDisplayController gives us a way to make the NativeDisplayDelegate
   // pretend something display related has happened.
   if (!base::SysInfo::IsRunningOnChromeOS()) {
     fake_display_controller_ =
         native_display_delegate->GetFakeDisplayController();
   }
 
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(

[rjkroege, 2016/11/21 21:19:11]

This doesn't seem like the right approach. The code invoking Init on the
PlatformScreen should say if it wants a configuration for internal or external
window mode. And it should know this based on how the WindowTree is built yes?
i.e. via WindowTreeFactory of WindowManagerWindowTreeFactory?

[Tom (Use chromium acct), 2016/11/22 02:48:15]

Done.

+          switches::kExternalWindowMode))
+    return;
+
   // We want display configuration to happen even off device to keep the control
   // flow similar.
   display_configurator_.set_configure_display(true);
   display_configurator_.AddObserver(this);
   display_configurator_.set_state_controller(this);
   display_configurator_.Init(std::move(native_display_delegate), false);
   display_configurator_.ForceInitialConfigure(kChromeOsBootColor);
 }
 
 void PlatformScreenOzone::RequestCloseDisplay(int64_t display_id) {
@@ skipping 281 matching lines @@
   return false;
 }
 
 void PlatformScreenOzone::Create(
     const service_manager::Identity& remote_identity,
     mojom::TestDisplayControllerRequest request) {
   test_bindings_.AddBinding(this, std::move(request));
 }
 
 }  // namespace display