Fix bug 175858: [Linux] The panel does not accept keyboard input when it is minimized and expanded

chrome/browser/ui/gtk/panels/panel_gtk.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 "chrome/browser/ui/gtk/panels/panel_gtk.h"
 
 #include <gdk/gdk.h>
 #include <gdk/gdkkeysyms.h>
 #include <X11/XF86keysym.h>
 
@@ skipping 805 matching lines @@
   panel_->OnNativePanelClosed();
 
   // We don't want GlobalMenuBar handling any notifications or commands after
   // the window is destroyed.
   // TODO(jennb):  global_menu_bar_->Disable();
   gtk_widget_destroy(window);
 }
 
 void PanelGtk::ActivatePanel() {
   gtk_window_present(window_);
+
+  // When the user clicks to expand the minimized panel, the panel has already
+  // become an active window before gtk_window_present is called. Thus the
+  // active window change event, fired by ActiveWindowWatcherXObserver, is not
+  // triggered. We need to call ActiveWindowChanged manually to update panel's
+  // active status. It is OK to call ActiveWindowChanged with the same active
+  // window twice since the 2nd call is just a no-op.
+  ActiveWindowChanged(gtk_widget_get_window(GTK_WIDGET(window_)));
 }
 
 void PanelGtk::DeactivatePanel() {
   gdk_window_lower(gtk_widget_get_window(GTK_WIDGET(window_)));
 
   // Per ICCCM: http://tronche.com/gui/x/icccm/sec-4.html#s-4.1.7
   // A convention is also required for clients that want to give up the
   // input focus. There is no safe value set for them to set the input
   // focus to; therefore, they should ignore input material.
   //
@@ skipping 333 matching lines @@
     default:
       NOTREACHED();
       return false;
   }
   return gtk_widget_get_visible(button->widget());
 }
 
 panel::CornerStyle GtkNativePanelTesting::GetWindowCornerStyle() const {
   return panel_gtk_->corner_style_;
 }