Changes the menu code to show mnemonics if the alt key is down.
Changes the menu code to show mnemonics if the alt key is down.

BUG=46445
TEST=press alt-f on windows and make sure the mnemonics are shown.

Review URL: http://codereview.chromium.org/2842041

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@51561 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser