Fix gcc warning in chrome os compile.

chrome/browser/automation/ui_controls_linux.cc

 // Copyright (c) 2009 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/automation/ui_controls.h"
 
 #include <gtk/gtk.h>
 #include <gdk/gdkkeysyms.h>
 
 #include "base/gfx/rect.h"
@@ skipping 259 matching lines @@
 
   g_object_ref(event->button.window);
   event->button.x = x;
   event->button.y = y;
   gint origin_x, origin_y;
   gdk_window_get_origin(event->button.window, &origin_x, &origin_y);
   event->button.x_root = x + origin_x;
   event->button.y_root = y + origin_y;
 
   event->button.axes = NULL;
-  gdk_window_get_pointer(event->button.window, NULL, NULL,
-      reinterpret_cast<GdkModifierType*>(&event->button.state));
+  GdkModifierType modifier;
+  gdk_window_get_pointer(event->button.window, NULL, NULL, &modifier);
+  event->button.state = modifier;
   event->button.button = type == LEFT ? 1 : (type == MIDDLE ? 2 : 3);
   event->button.device = gdk_device_get_core_pointer();
 
   event->button.type = GDK_BUTTON_PRESS;
   if (state & DOWN)
     gdk_event_put(event);
 
   // Also send a release event.
   GdkEvent* release_event = gdk_event_copy(event);
   release_event->button.type = GDK_BUTTON_RELEASE;
@@ skipping 42 matching lines @@
                                int state,
                                Task* task) {
   gfx::Rect bounds = gtk_util::GetWidgetScreenBounds(widget);
   SendMouseMoveNotifyWhenDone(bounds.x() + bounds.width() / 2,
                               bounds.y() + bounds.height() / 2,
                               new ClickTask(button, state, task));
 }
 #endif
 
 }  // namespace ui_controls