MessageBubble which does not require separate window and does not grab input on mouse press event.

views/widget/widget_gtk.h

 // Copyright (c) 2010 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_WIDGET_WIDGET_GTK_H_
 #define VIEWS_WIDGET_WIDGET_GTK_H_
 
 #include <gtk/gtk.h>
 
 #include "app/active_window_watcher_x.h"
@@ skipping 252 matching lines @@
   void set_mouse_down(bool mouse_down) { is_mouse_down_ = mouse_down; }
 
   // Do we own the mouse grab?
   bool has_capture() const { return has_capture_; }
 
   // Returns whether capture should be released on mouse release. The default
   // is true.
   virtual bool ReleaseCaptureOnMouseReleased() { return true; }
 
   // Does a mouse grab on this widget.
-  void DoGrab();
+  virtual void DoGrab();
 
   // Releases a grab done by this widget.
   virtual void ReleaseGrab();
 
+  // Invoked when input grab is stolen by other GtkWidget in the same
+  // application.
+  virtual void HandleGrabBroke();
+
   // Are we a subclass of WindowGtk?
   bool is_window_;
 
   // For test code to provide a customized focus manager.
   void set_focus_manager(FocusManager* focus_manager) {
     delete focus_manager_;
     focus_manager_ = focus_manager;
   }
 
  private:
@@ skipping 21 matching lines @@
   // Invoked from create widget to enable the various bits needed for a
   // transparent background. This is only invoked if MakeTransparent has been
   // invoked.
   void ConfigureWidgetForTransparentBackground(GtkWidget* parent);
 
   // Invoked from create widget to enable the various bits needed for a
   // window which doesn't receive events. This is only invoked if
   // MakeIgnoreEvents has been invoked.
   void ConfigureWidgetForIgnoreEvents();
 
-  // TODO(sky): documentation
-  void HandleGrabBroke();
-
   // A utility function to draw a transparent background onto the |widget|.
   static void DrawTransparentBackground(GtkWidget* widget,
                                         GdkEventExpose* event);
 
   const Type type_;
 
   // Our native views. If we're a window/popup, then widget_ is the window and
   // window_contents_ is a GtkFixed. If we're not a window/popup, then widget_
   // and window_contents_ point to the same GtkFixed.
   GtkWidget* widget_;
@@ skipping 102 matching lines @@
   // If true, we enable the content widget's double buffering.
   // This is false by default.
   bool is_double_buffered_;
 
   DISALLOW_COPY_AND_ASSIGN(WidgetGtk);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_WIDGET_WIDGET_GTK_H_