Don't allow drop to panels (pop-ups) in ChromeOS.

chrome/browser/views/tab_contents/tab_contents_view_gtk.cc

 // 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.
 
 #include "chrome/browser/views/tab_contents/tab_contents_view_gtk.h"
 
 #include <gdk/gdk.h>
 #include <gtk/gtk.h>
 
 #include "base/string_util.h"
@@ skipping 171 matching lines @@
   g_signal_connect(view->native_view(), "leave-notify-event",
                    G_CALLBACK(OnLeaveNotify2), tab_contents());
   g_signal_connect(view->native_view(), "motion-notify-event",
                    G_CALLBACK(CallMouseMove), this);
   g_signal_connect(view->native_view(), "scroll-event",
                    G_CALLBACK(OnMouseScroll), tab_contents());
   gtk_widget_add_events(view->native_view(), GDK_LEAVE_NOTIFY_MASK |
                         GDK_POINTER_MOTION_MASK);
 
   // Renderer target DnD.
-  drag_dest_.reset(new WebDragDestGtk(tab_contents(), view->native_view()));
+  if (tab_contents()->ShouldAcceptDragAndDrop())
+    drag_dest_.reset(new WebDragDestGtk(tab_contents(), view->native_view()));
 
   gtk_fixed_put(GTK_FIXED(GetNativeView()), view->native_view(), 0, 0);
   return view;
 }
 
 gfx::NativeView TabContentsViewGtk::GetNativeView() const {
   return WidgetGtk::GetNativeView();
 }
 
 gfx::NativeView TabContentsViewGtk::GetContentNativeView() const {
@@ skipping 110 matching lines @@
       // no longer be focusable (e.g. if the location bar was focused and then
       // we switched to fullscreen mode).  In that case we default to the
       // default focus.
       SetInitialFocus();
     }
     view_storage->RemoveView(last_focused_view_storage_id_);
   }
 }
 
 void TabContentsViewGtk::UpdateDragCursor(WebDragOperation operation) {
-  drag_dest_->UpdateDragStatus(operation);
+  if (drag_dest_.get())
+    drag_dest_->UpdateDragStatus(operation);
 }
 
 void TabContentsViewGtk::GotFocus() {
   if (tab_contents()->delegate())
     tab_contents()->delegate()->TabContentsFocused(tab_contents());
 }
 
 void TabContentsViewGtk::TakeFocus(bool reverse) {
   if (tab_contents()->delegate() &&
       !tab_contents()->delegate()->TakeFocus(reverse)) {
@@ skipping 116 matching lines @@
 // not NULL, else our delegate.
 gboolean TabContentsViewGtk::OnMouseMove(GtkWidget* widget,
                                          GdkEventMotion* event) {
   if (sad_tab_ != NULL)
     WidgetGtk::OnMotionNotify(widget, event);
   else if (tab_contents()->delegate())
     tab_contents()->delegate()->ContentsMouseEvent(
         tab_contents(), views::Screen::GetCursorScreenPoint(), true);
   return FALSE;
 }