Ignore invalid plugin windows coming in from the renderer for moving. As the plugin parent window which lives on the browser UI thread is destroyed asynchronously, we may have stale windows which have already been destroyed sent by the renderer for moving around.The DeferWindowPos API fails on receiving such a window.

Review URL: http://codereview.chromium.org/19523

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8994 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 1 deletions

diff --git a/chrome/browser/renderer_host/render_widget_host_view_win.cc b/chrome/browser/renderer_host/render_widget_host_view_win.cc
index 4459d26..2c19e7e 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_win.cc
+++ b/chrome/browser/renderer_host/render_widget_host_view_win.cc
@@ -158,6 +158,12 @@ void RenderWidgetHostViewWin::MovePluginWindows(
     unsigned long flags = 0;
     const WebPluginGeometry& move = plugin_window_moves[i];
 
+    // As the plugin parent window which lives on the browser UI thread is
+    // destroyed asynchronously, it is possible that we have a stale window
+    // sent in by the renderer for moving around.
+    if (!::IsWindow(move.window))
+      continue;
+
     if (move.visible)
       flags |= SWP_SHOWWINDOW;
     else
@@ -180,7 +186,7 @@ void RenderWidgetHostViewWin::MovePluginWindows(
                                              move.window_rect.width(),
                                              move.window_rect.height(), flags);
     if (!defer_window_pos_info) {
-      DCHECK(false) << "DeferWindowPos given invalid window, so rest ignored.";
+      DCHECK(false) << "DeferWindowPos failed, so all plugin moves ignored.";
       return;
     }
   }