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

views/controls/native/native_view_host_gtk.h

 // 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.
 
 #ifndef VIEWS_CONTROLS_NATIVE_HOST_VIEW_GTK_H_
 #define VIEWS_CONTROLS_NATIVE_HOST_VIEW_GTK_H_
 
 #include <gtk/gtk.h>
 #include <string>
 
 #include "base/gfx/rect.h"
 #include "base/logging.h"
 #include "views/controls/native/native_view_host_wrapper.h"
 
 namespace views {
 
 class View;
 class WidgetGtk;
 
+// Note that the NativeViewHostGtk assumes ownership of the GtkWidget attached
+// to it for the duration of its attachment. This is so the NativeViewHostGtk
+// can safely reparent the GtkWidget in multiple passes without having to worry
+// about the GtkWidget's refcnt falling to 0.
 class NativeViewHostGtk : public NativeViewHostWrapper {
  public:
   explicit NativeViewHostGtk(NativeViewHost* host);
   virtual ~NativeViewHostGtk();
 
   // Overridden from NativeViewHostWrapper:
   virtual void NativeViewAttached();
   virtual void NativeViewDetaching();
   virtual void AddedToWidget();
   virtual void RemovedFromWidget();
   virtual void InstallClip(int x, int y, int w, int h);
   virtual bool HasInstalledClip();
   virtual void UninstallClip();
   virtual void ShowWidget(int x, int y, int w, int h);
   virtual void HideWidget();
   virtual void SetFocus();
 
  private:
   // Create and Destroy the GtkFixed that performs clipping on our hosted
   // GtkWidget. |needs_window| is true when a clip is installed and implies the
   // fixed is backed by a X Window which actually performs the clipping.
   // It's kind of retarded that Gtk/Cairo doesn't clip painting of child windows
   // regardless of whether or not there's an X Window. It's not that hard.
   void CreateFixed(bool needs_window);
 
   // DestroyFixed returns true if an associated GtkWidget was addref'ed.

[jcampan, 2009/07/31 23:51:56]

It does not return anything anymore, fix comment.

   // It does this because when the fixed is destroyed the refcount for the
   // contained GtkWidget is decremented, which may cause it to be destroyed
-  // which we do not want. If this function returns true, the caller is
-  // responsible for unrefing the GtkWidget after it has been added to the new
-  // container.
-  bool DestroyFixed();
+  // which we do not want.
+  void DestroyFixed();
 
   WidgetGtk* GetHostWidget() const;
 
   // Invoked from the 'destroy' signal.
   static void CallDestroy(GtkObject* object, NativeViewHostGtk* host);
 
   // Our associated NativeViewHost.
   NativeViewHost* host_;
 
   // Have we installed a region on the gfx::NativeView used to clip to only the
@@ skipping 11 matching lines @@
   // clipping).
   GtkWidget* fixed_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeViewHostGtk);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_NATIVE_HOST_VIEW_GTK_H_