Fixes compile error in NativeMenuGtk when building for 64 bit.
Fixes compile error in NativeMenuGtk when building for 64 bit.

BUG=none
TEST=none


git-svn-id: http://src.chromium.org/svn/trunk/src@28544 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 49e620ee8992bd42c88d6f9fb0a66192b0812969
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser