Fix a potential access violation in the destructor of OmniboxViewWin.

Fix a potential access violation in the destructor of OmniboxViewWin.

If an OmniboxViewWin is created then destroyed without being used in the interim, the destructor would dereference a null pointer.

Discovered while writing https://chromiumcodereview.appspot.com/10854017

BUG=NONE
TEST=NONE

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=151712

[Peter Kasting, 2012-08-14 18:19:04]

LGTM, good catch!  It seems unlikely this has caused real crashes since
practically anything the omnibox does results in initializing this, but it's
good to be safe.

[commit-bot: I haz the power, 2012-08-14 19:01:58]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/robertshield@chromium.org/10826271/1

[commit-bot: I haz the power, 2012-08-14 20:40:13]

Try job failure for 10826271-1 (retry) on linux_rel for step
"interactive_ui_tests".
It's a second try, previously, step "interactive_ui_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_rel&...

[commit-bot: I haz the power, 2012-08-14 21:10:04]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/robertshield@chromium.org/10826271/1

[commit-bot: I haz the power, 2012-08-15 01:30:48]

Try job failure for 10826271-1 (retry) on linux_chromeos for step
"browser_tests".
It's a second try, previously, step "browser_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...

[commit-bot: I haz the power, 2012-08-15 02:04:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/robertshield@chromium.org/10826271/1

[commit-bot: I haz the power, 2012-08-15 03:30:15]

Try job failure for 10826271-1 (retry) on mac_rel for step "browser_tests".
It's a second try, previously, step "browser_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_rel&nu...