Start to decouple display::Display from ws::PlatformDisplay.

services/ui/ws/window_tree_host_factory.cc

Index: services/ui/ws/window_tree_host_factory.cc
diff --git a/services/ui/ws/window_tree_host_factory.cc b/services/ui/ws/window_tree_host_factory.cc
index 1a2170b0a67144aeeaf31f6260afcce47ada1e00..c1a140eba5c217a47416f291795b828a55870ef9 100644
--- a/services/ui/ws/window_tree_host_factory.cc
+++ b/services/ui/ws/window_tree_host_factory.cc
@@ -4,6 +4,7 @@
 
 #include "services/ui/ws/window_tree_host_factory.h"
 
+#include "services/ui/display/viewport_metrics.h"
 #include "services/ui/ws/display.h"
 #include "services/ui/ws/display_binding.h"
 #include "services/ui/ws/window_server.h"
@@ -13,12 +14,7 @@ namespace ws {
 
 WindowTreeHostFactory::WindowTreeHostFactory(WindowServer* window_server,
                                              const UserId& user_id)
-    : window_server_(window_server), user_id_(user_id) {
-  platform_display_init_params_.metrics.bounds.set_width(1024);
-  platform_display_init_params_.metrics.bounds.set_height(768);
-  platform_display_init_params_.metrics.pixel_size.SetSize(1024, 768);
-  platform_display_init_params_.metrics.device_scale_factor = 1.0f;
-}
+    : window_server_(window_server), user_id_(user_id) {}
 
 WindowTreeHostFactory::~WindowTreeHostFactory() {}
 
@@ -30,11 +26,22 @@ void WindowTreeHostFactory::AddBinding(
 void WindowTreeHostFactory::CreateWindowTreeHost(
     mojom::WindowTreeHostRequest host,
     mojom::WindowTreeClientPtr tree_client) {
-  Display* display = new Display(window_server_);
+  Display* ws_display = new Display(window_server_);
+
   std::unique_ptr<DisplayBindingImpl> display_binding(
-      new DisplayBindingImpl(std::move(host), display, user_id_,
+      new DisplayBindingImpl(std::move(host), ws_display, user_id_,
                              std::move(tree_client), window_server_));
-  display->Init(platform_display_init_params_, std::move(display_binding));
+
+  // Provide an initial size for the WindowTreeHost.
+  display::ViewportMetrics metrics;
+  metrics.bounds = gfx::Rect(1024, 768);
+  metrics.device_scale_factor = 1.0f;
+  metrics.ui_scale_factor = 1.0f;
+
+  display::Display display(1, metrics.bounds);
+  ws_display->SetDisplay(display);
+
+  ws_display->Init(metrics, std::move(display_binding));
 }
 
 }  // namespace ws