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..93c68748fee0c3aa37145354eac5beda59d16e4b 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
@@ -187,7 +187,7 @@ DesktopWindowTreeHostX11::DesktopWindowTreeHostX11(
       x_root_window_(DefaultRootWindow(xdisplay_)),
       atom_cache_(xdisplay_, kAtomsToCache),
       window_mapped_(false),
-      wait_for_unmap_(false),
+      is_visible_(false),
       is_fullscreen_(false),
       is_always_on_top_(false),
       use_native_frame_(false),
@@ -584,7 +584,7 @@ void DesktopWindowTreeHostX11::ShowMaximizedWithBounds(
 }
 
 bool DesktopWindowTreeHostX11::IsVisible() const {
-  return window_mapped_ && !wait_for_unmap_;
+  return is_visible_;
 }
 
 void DesktopWindowTreeHostX11::SetSize(const gfx::Size& requested_size) {
@@ -1198,7 +1198,7 @@ void DesktopWindowTreeHostX11::ShowImpl() {
 void DesktopWindowTreeHostX11::HideImpl() {
   if (IsVisible()) {
     XWithdrawWindow(xdisplay_, xwindow_, 0);
-    wait_for_unmap_ = true;
+    is_visible_ = false;
   }
   native_widget_delegate_->OnNativeWidgetVisibilityChanged(false);
 }
@@ -1216,9 +1216,12 @@ 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();
 
@@ -1897,19 +1900,10 @@ void DesktopWindowTreeHostX11::MapWindow(ui::WindowShowState show_state) {
   ui::X11EventSource* event_source = ui::X11EventSource::GetInstance();
   DCHECK(event_source);
 
-  if (wait_for_unmap_) {
-    // Block until our window is unmapped. This avoids a race condition when
-    // remapping an unmapped window.
-    event_source->BlockUntilWindowUnmapped(xwindow_);
-    DCHECK(!wait_for_unmap_);
-  }
+  UpdateMinAndMaxSize();
 
   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_);
+  is_visible_ = true;
 }
 
 void DesktopWindowTreeHostX11::SetWindowTransparency() {
@@ -2138,8 +2132,6 @@ uint32_t DesktopWindowTreeHostX11::DispatchEvent(
                         observer_list_,
                         OnWindowMapped(xwindow_));
 
-      UpdateMinAndMaxSize();
-
       // Some WMs only respect maximize hints after the window has been mapped.
       // Check whether we need to re-do a maximization.
       if (should_maximize_after_map_) {
@@ -2151,7 +2143,6 @@ uint32_t DesktopWindowTreeHostX11::DispatchEvent(
     }
     case UnmapNotify: {
       window_mapped_ = false;
-      wait_for_unmap_ = false;
       has_pointer_ = false;
       has_pointer_grab_ = false;
       has_pointer_focus_ = false;