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

Spend around 2 days with reproducing the problem, checking out the underlying code, and discussing with others (see bug for more info) without further insights. Since the bug is gone with v22 and we might get more data if it crashes later, we hope that this is an adequate solution for the problem (even though it is not satisfying).


BUG=134465
TEST=NONE and not reproducible


Review URL: https://chromiumcodereview.appspot.com/10790058

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@147982 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/renderer_host/render_widget_host_impl.cc

@@ -885,7 +885,11 @@ 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,