RenderWidgetHostView: Fix a crash that occurrs when the TabContents is being

destroyed but the win32 message loop sends a late message.

BUG=102008
TEST=none

R=sky@chromium.org

Review URL: http://codereview.chromium.org/8416023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107783 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/renderer_host/render_widget_host_view_win.cc

@@ -331,7 +331,11 @@ void RenderWidgetHostViewWin::DidBecomeSelected() {
     tab_switch_paint_time_ = TimeTicks::Now();
   is_hidden_ = false;
   EnsureTooltip();
-  render_widget_host_->WasRestored();
+
+  // |render_widget_host_| may be NULL if the TabContents is in the process of
+  // closing.
+  if (render_widget_host_)
+    render_widget_host_->WasRestored();
 }
 
 void RenderWidgetHostViewWin::WasHidden() {