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

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 862 matching lines @@
       // RawKeyDown event may generate multiple Char events, so we can't reset
       // |suppress_next_char_events_| until we get a KeyUp or a RawKeyDown.
       if (key_event.type == WebKeyboardEvent::Char)
         return;
       // We get a KeyUp or a RawKeyDown event.
       suppress_next_char_events_ = false;
     }
 
     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,
       // then revert it afterwards when necessary.
       if (key_event.type == WebKeyboardEvent::RawKeyDown)
         suppress_next_char_events_ = true;
 
       // Tab switching/closing accelerators aren't sent to the renderer to avoid
       // a hung/malicious renderer from interfering.
       if (delegate_->PreHandleKeyboardEvent(key_event, &is_keyboard_shortcut))
@@ skipping 1014 matching lines @@
   // indicate that no callback is in progress (i.e. without this line
   // DelayedAutoResized will not get called again).
   new_auto_size_.SetSize(0, 0);
   if (!should_auto_resize_)
     return;
 
   OnRenderAutoResized(new_size);
 }
 
 }  // namespace content