We allow Flash to popup windows in response to user gesture messages like WM_...

webkit/glue/plugins/webplugin_delegate_impl.cc

 // Copyright (c) 2006-2008 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 "webkit/glue/plugins/webplugin_delegate_impl.h"
 
 #include <string>
 #include <vector>
 
 #include "base/file_util.h"
@@ skipping 25 matching lines @@
 // Flash can easily exceed the limits of our CPU if we don't throttle it.
 // The throttle has been chosen by testing various delays and compromising
 // on acceptable Flash performance and reasonable CPU consumption.
 //
 // I'd like to make the throttle delay variable, based on the amount of
 // time currently required to paint Flash plugins.  There isn't a good
 // way to count the time spent in aggregate plugin painting, however, so
 // this seems to work well enough.
 const int kFlashWMUSERMessageThrottleDelayMs = 5;
 
+// Flash displays popups in response to user clicks by posting a WM_USER
+// message to the plugin window. The handler for this message displays
+// the popup. To ensure that the popups allowed state is sent correctly
+// to the renderer we reset the popups allowed state in a timer.
+const int kWindowedPluginPopupTimerMs = 50;
+
 // The current instance of the plugin which entered the modal loop.
 WebPluginDelegateImpl* g_current_plugin_instance = NULL;
 
 base::LazyInstance<std::list<MSG> > g_throttle_queue(base::LINKER_INITIALIZED);
 
 // Helper object for patching the TrackPopupMenu API.
 base::LazyInstance<iat_patch::IATPatchFunction> g_iat_patch_track_popup_menu(
     base::LINKER_INITIALIZED);
 
 // Helper object for patching the SetCursor API.
@@ skipping 821 matching lines @@
 
   delegate->last_message_ = message;
   delegate->is_calling_wndproc = true;
 
   if (!delegate->user_gesture_message_posted_ &&
        IsUserGestureMessage(message)) {
     delegate->user_gesture_message_posted_ = true;
 
     delegate->instance()->PushPopupsEnabledState(true);
 
-    MessageLoop::current()->PostTask(FROM_HERE,
+    MessageLoop::current()->PostDelayedTask(FROM_HERE,
         delegate->user_gesture_msg_factory_.NewRunnableMethod(
-            &WebPluginDelegateImpl::OnUserGestureEnd));
+            &WebPluginDelegateImpl::OnUserGestureEnd),
+        kWindowedPluginPopupTimerMs);
   }
 
   LRESULT result = CallWindowProc(delegate->plugin_wnd_proc_, hwnd, message,
                                   wparam, lparam);
   delegate->is_calling_wndproc = false;
   g_current_plugin_instance = last_plugin_instance;
   return result;
 }
 
 void WebPluginDelegateImpl::WindowlessUpdateGeometry(
@@ skipping 288 matching lines @@
 
   // It is ok to pass NULL here to GetCursor as we are not looking for cursor
   // types defined by Webkit.
   HCURSOR previous_cursor =
       g_current_plugin_instance->current_windowless_cursor_.GetCursor(NULL);
 
   g_current_plugin_instance->current_windowless_cursor_.InitFromExternalCursor(
       cursor);
   return previous_cursor;
 }