Workaround a crash occuring only in v20 and v21 without a repro case (need more data for good fix)

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index e8b5dcbc5b6e19f672fe80df2a1df6617068b40d..7fe153e88b93b67960da333e195bf304d0748d04 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -880,7 +880,11 @@ void RenderWidgetHostImpl::ForwardKeyboardEvent(
 
     bool is_keyboard_shortcut = false;
     // Only pre-handle the key event if it's not handled by the input method.
-    if (!key_event.skip_in_browser) {
+    // A delegate_ of NULL seems impossible but crash reports show that it
+    // can happen (see http://crbug.com/134465). This doesn't seem to happen
+    // with Chrome 22 and later, so checking the delegate_ here can be removed
+    // once Chrome 22 goes to stable..
+    if (delegate_ && !key_event.skip_in_browser) {
       // We need to set |suppress_next_char_events_| to true if
       // PreHandleKeyboardEvent() returns true, but |this| may already be
       // destroyed at that time. So set |suppress_next_char_events_| true here,