Fix code to get widget position on screen.

views/widget/widget_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/widget/widget_gtk.h"
 
 #include "app/drag_drop_types.h"
 #include "app/gfx/path.h"
 #include "app/os_exchange_data.h"
 #include "app/os_exchange_data_provider_gtk.h"
@@ skipping 33 matching lines @@
       return NULL;
 
     return WidgetGtk::GetViewForNative(gtk_widget);
   }
 
   DISALLOW_COPY_AND_ASSIGN(DropObserver);
 };
 
 // Returns the position of a widget on screen.
 static void GetWidgetPositionOnScreen(GtkWidget* widget, int* x, int *y) {
-  while (widget) {
-    if (GTK_IS_WINDOW(widget)) {
-      int window_x, window_y;
-      gtk_window_get_position(GTK_WINDOW(widget), &window_x, &window_y);
-      *x += window_x;
-      *y += window_y;
-      return;
-    }
-    // Not a window.
-    *x += widget->allocation.x;
-    *y += widget->allocation.y;
-    widget = gtk_widget_get_parent(widget);
+  // First get the root window.
+  GtkWidget* root = widget;
+  while (root && !GTK_IS_WINDOW(root)) {
+    root = gtk_widget_get_parent(root);
   }
+  DCHECK(root);
+  // Translate the coordinate from widget to root window.
+  gtk_widget_translate_coordinates(widget, root, 0, 0, x, y);
+  // Then adjust the position with the position of the root window.
+  int window_x, window_y;
+  gtk_window_get_position(GTK_WINDOW(root), &window_x, &window_y);
+  *x += window_x;
+  *y += window_y;
 }
 
 // Returns the view::Event::flags for a GdkEventButton.
 static int GetFlagsForEventButton(const GdkEventButton& event) {
   int flags = Event::GetFlagsFromGdkState(event.state);
   switch (event.button) {
     case 1:
       flags |= Event::EF_LEFT_BUTTON_DOWN;
       break;
     case 2:
@@ skipping 1032 matching lines @@
 
 // static
 Widget* Widget::CreateTransparentPopupWidget(bool delete_on_destroy) {
   WidgetGtk* popup = new WidgetGtk(WidgetGtk::TYPE_POPUP);
   popup->set_delete_on_destroy(delete_on_destroy);
   popup->MakeTransparent();
   return popup;
 }
 
 }  // namespace views