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

services/ui/ws/window_server.cc

Index: services/ui/ws/window_server.cc
diff --git a/services/ui/ws/window_server.cc b/services/ui/ws/window_server.cc
index a1a67187ffb9ada208d3a6b522edd8f6c0aed92e..b7864006819e66d98a91c8ccd701ecf735e997fb 100644
--- a/services/ui/ws/window_server.cc
+++ b/services/ui/ws/window_server.cc
@@ -193,6 +193,12 @@ WindowTree* WindowServer::GetTreeWithClientName(
   return nullptr;
 }
 
+WindowTree* WindowServer::GetTreeForExternalWindowMode() {
+  DCHECK_LE(1u, tree_map_.size());
+  DCHECK(IsInExternalWindowMode());
+  return tree_map_.begin()->second.get();
+}
+
 ServerWindow* WindowServer::GetWindow(const WindowId& id) {
   // kInvalidClientId is used for Display and WindowManager nodes.
   if (id.client_id == kInvalidClientId) {
@@ -579,7 +585,7 @@ void WindowServer::FinishOperation() {
 void WindowServer::UpdateNativeCursorFromMouseLocation(ServerWindow* window) {
   WindowManagerDisplayRoot* display_root =
       display_manager_->GetWindowManagerDisplayRoot(window);
-  if (display_root) {
+  if (display_root && display_root->window_manager_state()) {
     EventDispatcher* event_dispatcher =
         display_root->window_manager_state()->event_dispatcher();
     event_dispatcher->UpdateCursorProviderByLastKnownLocation();
@@ -591,7 +597,7 @@ void WindowServer::UpdateNativeCursorFromMouseLocation(ServerWindow* window) {
 void WindowServer::UpdateNativeCursorIfOver(ServerWindow* window) {
   WindowManagerDisplayRoot* display_root =
       display_manager_->GetWindowManagerDisplayRoot(window);
-  if (!display_root)
+  if (!display_root || !display_root->window_manager_state())
     return;
 
   EventDispatcher* event_dispatcher =
@@ -665,7 +671,7 @@ void WindowServer::OnWindowHierarchyChanged(ServerWindow* window,
 
   WindowManagerDisplayRoot* display_root =
       display_manager_->GetWindowManagerDisplayRoot(window);
-  if (display_root)
+  if (display_root && display_root->window_manager_state())
     display_root->window_manager_state()
         ->ReleaseCaptureBlockedByAnyModalWindow();
 
@@ -744,7 +750,7 @@ void WindowServer::OnWindowVisibilityChanged(ServerWindow* window) {
 
   WindowManagerDisplayRoot* display_root =
       display_manager_->GetWindowManagerDisplayRoot(window);
-  if (display_root)
+  if (display_root && display_root->window_manager_state())
     display_root->window_manager_state()->ReleaseCaptureBlockedByModalWindow(
         window);
 }