c++ / mojo changes for 'external window mode'

services/ui/ws/display.cc

Index: services/ui/ws/display.cc
diff --git a/services/ui/ws/display.cc b/services/ui/ws/display.cc
index b3981b86032061140d6c25279a890a940e863eab..839656fd582a907aa6fedfb1b779e355dac9fd72 100644
--- a/services/ui/ws/display.cc
+++ b/services/ui/ws/display.cc
@@ -26,6 +26,7 @@
 #include "services/ui/ws/window_server_delegate.h"
 #include "services/ui/ws/window_tree.h"
 #include "services/ui/ws/window_tree_binding.h"
+#include "services/ui/ws/window_tree_host_factory.h"
 #include "ui/base/cursor/cursor.h"
 
 namespace ui {
@@ -62,6 +63,9 @@ Display::~Display() {
 
 void Display::Init(const PlatformDisplayInitParams& init_params,
                    std::unique_ptr<DisplayBinding> binding) {
+  in_external_window_mode_ =
+      window_server_->window_tree_host_factory() && binding;
+
   binding_ = std::move(binding);
   display_manager()->AddDisplay(this);
 
@@ -204,7 +208,26 @@ void Display::SetTitle(const std::string& title) {
   platform_display_->SetTitle(base::UTF8ToUTF16(title));
 }
 
+void Display::InitDisplayRoot() {
+  DCHECK(in_external_window_mode_);
+  DCHECK(binding_);
+  DCHECK(window_server_->window_tree_host_factory());
+
+  external_window_mode_display_root_ =
+      base::MakeUnique<WindowManagerDisplayRoot>(this);
+  window_manager_display_root_map_[service_manager::mojom::kRootUserID] =
+      external_window_mode_display_root_.get();
+
+  ServerWindow* server_window = external_window_mode_display_root_->root();
+  WindowTree* window_tree =
+      window_server_->window_tree_host_factory()->window_tree();
+  window_tree->AddRoot(server_window);
+  window_tree->DoOnEmbed(nullptr /*mojom::WindowTreePtr*/, server_window);
+}
+
 void Display::InitWindowManagerDisplayRoots() {
+  // Tests can create ws::Display instances, directly by-passing
+  // WindowTreeHostFactory.
   if (binding_) {
     std::unique_ptr<WindowManagerDisplayRoot> display_root_ptr(
         new WindowManagerDisplayRoot(this));
@@ -220,7 +243,6 @@ void Display::InitWindowManagerDisplayRoots() {
   } else {
     CreateWindowManagerDisplayRootsFromFactories();
   }
-  display_manager()->OnDisplayUpdate(this);
 }
 
 void Display::CreateWindowManagerDisplayRootsFromFactories() {
@@ -274,7 +296,13 @@ ServerWindow* Display::GetRootWindow() {
 
 void Display::OnAcceleratedWidgetAvailable() {
   display_manager()->OnDisplayAcceleratedWidgetAvailable(this);
-  InitWindowManagerDisplayRoots();
+
+  if (in_external_window_mode_)
+    InitDisplayRoot();
+  else
+    InitWindowManagerDisplayRoots();
+
+  display_manager()->OnDisplayUpdate(this);
 }
 
 bool Display::IsInHighContrastMode() {