Fix two crashers with TOOLKIT_VIEWS build:...

views/controls/native/native_view_host_gtk.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 "views/controls/native/native_view_host_gtk.h"
 
 #include <gtk/gtk.h>
 
 #include "base/logging.h"
 #include "views/controls/native/native_view_host.h"
@@ skipping 69 matching lines @@
   host_->Layout();
 }
 
 void NativeViewHostGtk::RemovedFromWidget() {
   if (!host_->native_view())
     return;
 
   WidgetGtk* parent_widget = GetHostWidget();
   gtk_widget_hide(host_->native_view());
   if (parent_widget) {
-    gtk_container_remove(GTK_CONTAINER(parent_widget->window_contents()),
-                         host_->native_view());
+    // We can be called after the contents widget has been destroyed, e.g. any
+    // NativeViewHost not removed from the view hierarchy before the window is
+    // closed.
+    if (GTK_IS_CONTAINER(parent_widget->window_contents())) {
+      gtk_container_remove(GTK_CONTAINER(parent_widget->window_contents()),
+                           host_->native_view());
+    }
   }
 }
 
 void NativeViewHostGtk::InstallClip(int x, int y, int w, int h) {
   DCHECK(w > 0 && h > 0);
 
   bool has_window =
       (GTK_WIDGET_FLAGS(host_->native_view()) & GTK_NO_WINDOW) == 0;
   if (!has_window) {
     // Clip is only supported on GtkWidgets that have windows. If this becomes
@@ skipping 57 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // NativeViewHostWrapper, public:
 
 // static
 NativeViewHostWrapper* NativeViewHostWrapper::CreateWrapper(
     NativeViewHost* host) {
   return new NativeViewHostGtk(host);
 }
 
 }  // namespace views