Avoid blocking while mapping an X11 window

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
index 66a424a3b2fa782de0337b0d6a267aecb136b1a5..128887af23a76e9dc6430e548365944a0c30d438 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
@@ -187,6 +187,7 @@ DesktopWindowTreeHostX11::DesktopWindowTreeHostX11(
       x_root_window_(DefaultRootWindow(xdisplay_)),
       atom_cache_(xdisplay_, kAtomsToCache),
       window_mapped_(false),
+      wait_for_map_(false),
       wait_for_unmap_(false),
       is_fullscreen_(false),
       is_always_on_top_(false),
@@ -584,7 +585,7 @@ void DesktopWindowTreeHostX11::ShowMaximizedWithBounds(
 }
 
 bool DesktopWindowTreeHostX11::IsVisible() const {
-  return window_mapped_ && !wait_for_unmap_;
+  return wait_for_map_ || (window_mapped_ && !wait_for_unmap_);
 }
 
 void DesktopWindowTreeHostX11::SetSize(const gfx::Size& requested_size) {
@@ -1199,6 +1200,7 @@ void DesktopWindowTreeHostX11::HideImpl() {
   if (IsVisible()) {
     XWithdrawWindow(xdisplay_, xwindow_, 0);
     wait_for_unmap_ = true;
+    wait_for_map_ = false;
   }
   native_widget_delegate_->OnNativeWidgetVisibilityChanged(false);
 }
@@ -1216,9 +1218,12 @@ void DesktopWindowTreeHostX11::SetBounds(
   XWindowChanges changes = {0};
   unsigned value_mask = 0;
 
-  delayed_resize_task_.Cancel();
 
   if (size_changed) {
+    // Only cancel the delayed resize task if we're already about to call
+    // OnHostResized in this function.
+    delayed_resize_task_.Cancel();
+
     // Update the minimum and maximum sizes in case they have changed.
     UpdateMinAndMaxSize();
 
@@ -1905,11 +1910,7 @@ void DesktopWindowTreeHostX11::MapWindow(ui::WindowShowState show_state) {
   }
 
   XMapWindow(xdisplay_, xwindow_);
-
-  // We now block until our window is mapped. Some X11 APIs will crash and
-  // burn if passed |xwindow_| before the window is mapped, and XMapWindow is
-  // asynchronous.
-  event_source->BlockUntilWindowMapped(xwindow_);
+  wait_for_map_ = true;
 }
 
 void DesktopWindowTreeHostX11::SetWindowTransparency() {
@@ -2132,6 +2133,7 @@ uint32_t DesktopWindowTreeHostX11::DispatchEvent(
       break;
     }
     case MapNotify: {
+      wait_for_map_ = false;
       window_mapped_ = true;
 
       FOR_EACH_OBSERVER(DesktopWindowTreeHostObserverX11,