Fix leak of GtkWidgets in NativeViewHost, and in doing so fix a crash on shut...

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 29 matching lines @@
 
   if (!destroy_signal_id_) {
     destroy_signal_id_ = g_signal_connect(G_OBJECT(host_->native_view()),
                                           "destroy", G_CALLBACK(CallDestroy),
                                           this);
   }
 
   // Always layout though.
   host_->Layout();
 
+  // We own the native view as long as it's attached, so that we can safely
+  // reparent it in multiple passes.
+  gtk_widget_ref(host_->native_view());
+
   // TODO(port): figure out focus.
 }
 
 void NativeViewHostGtk::NativeViewDetaching() {
   DCHECK(host_->native_view());
 
   g_signal_handler_disconnect(G_OBJECT(host_->native_view()),
                               destroy_signal_id_);
   destroy_signal_id_ = 0;
 
   // TODO(port): focus.
   // FocusManager::UninstallFocusSubclass(native_view());
   installed_clip_ = false;
+
+  // Release ownership back to the caller.
+  gtk_widget_unref(host_->native_view());
 }
 
 void NativeViewHostGtk::AddedToWidget() {
   if (gtk_widget_get_parent(fixed_))
     GetHostWidget()->ReparentChild(fixed_);
   else
     GetHostWidget()->AddChild(fixed_);
 
   if (!host_->native_view())
     return;
 
   if (gtk_widget_get_parent(host_->native_view()))
     gtk_widget_reparent(host_->native_view(), fixed_);
   else
     gtk_container_add(GTK_CONTAINER(fixed_), host_->native_view());
 
   if (host_->IsVisibleInRootView())
     gtk_widget_show(fixed_);
   else
     gtk_widget_hide(fixed_);
   host_->Layout();
 }
 
 void NativeViewHostGtk::RemovedFromWidget() {
   if (!host_->native_view())
     return;
 
-  // TODO(beng): We leak host_->native_view() here. Fix: make all widgets not be
-  //             refcounted.
   DestroyFixed();
 }
 
 void NativeViewHostGtk::InstallClip(int x, int y, int w, int h) {
   DCHECK(w > 0 && h > 0);
   installed_clip_bounds_.SetRect(x, y, w, h);
   installed_clip_ = true;
 
   // We only re-create the fixed with a window when a cliprect is installed.
   // Because the presence of a X Window will prevent transparency from working
@@ skipping 47 matching lines @@
 }
 
 void NativeViewHostGtk::SetFocus() {
   NOTIMPLEMENTED();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeViewHostGtk, private:
 
 void NativeViewHostGtk::CreateFixed(bool needs_window) {
-  bool native_view_addrefed = DestroyFixed();
+  DestroyFixed();
 
   fixed_ = gtk_fixed_new();
   gtk_fixed_set_has_window(GTK_FIXED(fixed_), needs_window);
   // Defeat refcounting. We need to own the fixed.
   gtk_widget_ref(fixed_);
 
   WidgetGtk* widget_gtk = GetHostWidget();
   if (widget_gtk)
     widget_gtk->AddChild(fixed_);
   if (host_->native_view())
     gtk_container_add(GTK_CONTAINER(fixed_), host_->native_view());
-  if (native_view_addrefed)
-    gtk_widget_unref(host_->native_view());
 }
 
-bool NativeViewHostGtk::DestroyFixed() {
-  bool native_view_addrefed = false;
+void NativeViewHostGtk::DestroyFixed() {
   if (!fixed_)
-    return native_view_addrefed;
+    return;
 
   gtk_widget_hide(fixed_);
   GetHostWidget()->RemoveChild(fixed_);
 
   if (host_->native_view()) {
-    // We can't allow the hosted NativeView's refcount to drop to zero.
-    gtk_widget_ref(host_->native_view());
-    native_view_addrefed = true;
+    // We can safely remove the widget from its container since we own the
+    // widget from the moment it is attached.
     gtk_container_remove(GTK_CONTAINER(fixed_), host_->native_view());
   }
 
   gtk_widget_destroy(fixed_);
   fixed_ = NULL;
-  return native_view_addrefed;
 }
 
 WidgetGtk* NativeViewHostGtk::GetHostWidget() const {
   return static_cast<WidgetGtk*>(host_->GetWidget());
 }
 
 // static
 void NativeViewHostGtk::CallDestroy(GtkObject* object,
                                     NativeViewHostGtk* host) {
   return host->host_->NativeViewDestroyed();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeViewHostWrapper, public:
 
 // static
 NativeViewHostWrapper* NativeViewHostWrapper::CreateWrapper(
     NativeViewHost* host) {
   return new NativeViewHostGtk(host);
 }
 
 }  // namespace views