chromeos: changes how DisplayManagerObservers are notified

ash/mus/display_synchronizer.cc

Index: ash/mus/display_synchronizer.cc
diff --git a/ash/mus/display_synchronizer.cc b/ash/mus/display_synchronizer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f948e2f9cc6d4995dac57763db9e3ded76a39189
--- /dev/null
+++ b/ash/mus/display_synchronizer.cc
@@ -0,0 +1,57 @@
+// 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 "ash/mus/display_synchronizer.h"
+
+#include "ash/shell.h"
+#include "ui/aura/mus/window_manager_delegate.h"
+#include "ui/display/manager/display_manager.h"
+#include "ui/display/manager/managed_display_info.h"
+
+namespace ash {
+
+DisplaySynchronizer::DisplaySynchronizer(
+    aura::WindowManagerClient* window_manager_client)
+    : window_manager_client_(window_manager_client) {
+  Shell::Get()->window_tree_host_manager()->AddObserver(this);
+  SendDisplayConfigurationToServer();
+}
+
+DisplaySynchronizer::~DisplaySynchronizer() {
+  Shell::Get()->window_tree_host_manager()->RemoveObserver(this);
+}
+
+void DisplaySynchronizer::SendDisplayConfigurationToServer() {
+  display::DisplayManager* display_manager = Shell::Get()->display_manager();
+  const size_t display_count = display_manager->GetNumDisplays();
+  if (display_count == 0)
+    return;
+
+  std::vector<display::Display> displays;
+  std::vector<ui::mojom::WmViewportMetricsPtr> metrics;
+  for (size_t i = 0; i < display_count; ++i) {
+    displays.push_back(display_manager->GetDisplayAt(i));
+    ui::mojom::WmViewportMetricsPtr viewport_metrics =
+        ui::mojom::WmViewportMetrics::New();
+    const display::ManagedDisplayInfo& display_info =
+        display_manager->GetDisplayInfo(displays.back().id());
+    viewport_metrics->bounds_in_pixels = display_info.bounds_in_native();
+    viewport_metrics->device_scale_factor = display_info.device_scale_factor();
+    viewport_metrics->ui_scale_factor = display_info.configured_ui_scale();
+    metrics.push_back(std::move(viewport_metrics));
+  }
+  window_manager_client_->SetDisplayConfiguration(
+      displays, std::move(metrics),
+      WindowTreeHostManager::GetPrimaryDisplayId());
+}
+
+void DisplaySynchronizer::OnDisplaysInitialized() {
+  SendDisplayConfigurationToServer();
+}
+
+void DisplaySynchronizer::OnDisplayConfigurationChanged() {
+  SendDisplayConfigurationToServer();
+}
+
+}  // namespace ash