X11: Fix test flakes related to window focus

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h"
 
 #include <X11/extensions/shape.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xregion.h>
@@ skipping 157 matching lines @@
     case XINotifyPassiveUngrab:
       return NotifyUngrab;
     case XINotifyWhileGrabbed:
       return NotifyWhileGrabbed;
     default:
       NOTREACHED();
       return NotifyNormal;
   }
 }
 
+int IgnoreX11Errors(XDisplay* display, XErrorEvent* error) {
+  return 0;
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostX11, public:
 
 DesktopWindowTreeHostX11::DesktopWindowTreeHostX11(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura)
     : xdisplay_(gfx::GetXDisplay()),
       xwindow_(0),
@@ skipping 605 matching lines @@
     // service our _NET_ACTIVE_WINDOW request.
     xclient.xclient.data.l[2] = None;
     xclient.xclient.data.l[3] = 0;
     xclient.xclient.data.l[4] = 0;
 
     XSendEvent(xdisplay_, x_root_window_, False,
                SubstructureRedirectMask | SubstructureNotifyMask, &xclient);
   } else {
     XRaiseWindow(xdisplay_, xwindow_);
     // Directly ask the X server to give focus to the window. Note that the call
-    // will raise an X error if the window is not mapped.
+    // would have raised an X error if the window is not mapped.
+    auto old_error_handler = XSetErrorHandler(IgnoreX11Errors);
     XSetInputFocus(xdisplay_, xwindow_, RevertToParent, timestamp);
-    // At this point, we know we will receive focus, and some tests depend on a
-    // window being IsActive() immediately after an Activate(), so just set this
-    // state now.
-    has_pointer_focus_ = false;
-    has_window_focus_ = true;
+    XSetErrorHandler(old_error_handler);
   }
   AfterActivationStateChanged();
 }
 
 void DesktopWindowTreeHostX11::Deactivate() {
   BeforeActivationStateChanged();
 
   // Ignore future input events.
   ignore_keyboard_input_ = true;
 
@@ skipping 1530 matching lines @@
 
 // static
 DesktopWindowTreeHost* DesktopWindowTreeHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura) {
   return new DesktopWindowTreeHostX11(native_widget_delegate,
                                       desktop_native_widget_aura);
 }
 
 }  // namespace views