Defer window destruction until GPU finished drawing.

gfx/gtk_native_view_id_manager.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 GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_
 #define GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_
 #pragma once
 
 #include <map>
 
@@ skipping 52 matching lines @@
   // widget to create a window.
   //
   // Keeping the XID permanent requires a bit of overhead, so it must
   // be explicitly requested.
   //
   // xid: (output) the resulting X window
   // id: a value previously returned from GetIdForWidget
   // returns: true if |id| is a valid id, false otherwise.
   bool GetPermanentXIDForId(XID* xid, gfx::NativeViewId id);
 
+  // Must be called from the UI thread because we may need to access a
+  // GtkWidget or destroy a GdkWindow.
+  //
+  // If the widget associated with the XID is still alive, release the lock

[piman, 2010/11/29 21:59:01]

You're talking about a lock here, but it's unclear from the user's pov what is
that lock. I assume you mean this releases the permanent XID.

+  // on the XID associated with a widget. Otherwise, destroy the GdkWindow
+  // associated with the XID.
+  void ReleasePermanentXID(XID xid);
+
   // These are actually private functions, but need to be called from statics.
   void OnRealize(gfx::NativeView widget);
   void OnUnrealize(gfx::NativeView widget);
   void OnDestroy(gfx::NativeView widget);
 
   Lock& unrealize_lock() { return unrealize_lock_; }
 
  private:
   // This object is a singleton:
   GtkNativeViewManager();
@@ skipping 15 matching lines @@
   Lock unrealize_lock_;
 
   // protects native_view_to_id_ and id_to_info_
   Lock lock_;
 
   // If asked for an id for the same widget twice, we want to return the same
   // id. So this records the current mapping.
   std::map<gfx::NativeView, gfx::NativeViewId> native_view_to_id_;
   std::map<gfx::NativeViewId, NativeViewInfo> id_to_info_;
 
+  // Mapping from X window to associated widget.
+  //
+  // In general, several GTK widgets may share the same X window. We assume
+  // that is not true of widgets in this registry.
+  //
+  // An XID will map to NULL, if the widget had been instructed to preserve
+  // it's X window, but was destroyed. In this case, the destruction is deferred

[piman, 2010/11/29 21:59:01]

it's->its

[jonathan.backer, 2010/11/30 13:09:31]

Done.

+  // until a call to ReleasePermXID.

[piman, 2010/11/29 21:59:01]

ReleasePermXID -> ReleasePermanentXID

[jonathan.backer, 2010/11/30 13:09:31]

Done.

+  std::map<XID, gfx::NativeView> xid_to_native_view_;
+
   DISALLOW_COPY_AND_ASSIGN(GtkNativeViewManager);
 };
 
 #endif  // GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_