Center the disconnect window at the bottom of the screen.

remoting/host/disconnect_window_mac.mm

Index: remoting/host/disconnect_window_mac.mm
diff --git a/remoting/host/disconnect_window_mac.mm b/remoting/host/disconnect_window_mac.mm
index 94ba85508b8779610f00504a3d59058441ed57f2..c3de197136e211f20e4a4e331b90935a87cea432 100644
--- a/remoting/host/disconnect_window_mac.mm
+++ b/remoting/host/disconnect_window_mac.mm
@@ -155,6 +155,13 @@ remoting::DisconnectWindow* remoting::DisconnectWindow::Create() {
     [connectedToField_ setFrame:connectedToFrame];
     [disconnectButton_ setFrame:disconnectFrame];
   }
+
+  // Center the window at the bottom of the screen, above the dock (if present).
+  NSRect desktopRect = [[NSScreen mainScreen] visibleFrame];
+  NSRect windowRect = [[self window] frame];
+  CGFloat x = (NSWidth(desktopRect) - NSWidth(windowRect)) / 2;
+  CGFloat y = NSMinY(desktopRect);
+  [[self window] setFrameOrigin:NSMakePoint(x, y)];
 }
 
 - (void)windowWillClose:(NSNotification*)notification {