Removes specifying transient at the aura level for top levels

This causes problems as it means the aura::Window may be deleted out
from under the DesktopNativeWidgetAura, which causes all sorts of woe.

This code is no longer needed since DesktopWindowTreeHostX11 now deals
with owned windows.

BUG=344265
TEST=none
R=erg@chromium.org

Review URL: https://codereview.chromium.org/186483007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255377 0039d316-1c4b-4281-b951-d872f2087c98

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

@@ -238,13 +238,6 @@ void DesktopWindowTreeHostX11::OnRootWindowCreated(
                                      content_window_);
   dispatcher_->window()->SetProperty(kHostForRootWindow, this);
 
-  // If we're given a parent, we need to mark ourselves as transient to another
-  // window. Otherwise activation gets screwy.
-  gfx::NativeView parent = params.parent;
-  if (!params.child && params.parent) {
-    corewm::AddTransientChild(parent, content_window_);
-  }
-
   // Ensure that the X11DesktopHandler exists so that it dispatches activation
   // messages to us.
   X11DesktopHandler::get();