Add libxkbcommon-dev to install-build-deps

We'll use this under ChromeOS ozone/freon builds for keyboard layout
support.

BUG=362698
TEST=ran install-build-deps.sh on trusty

Review URL: https://codereview.chromium.org/488833003

Cr-Commit-Position: refs/heads/master@{#290727}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@290727 0039d316-1c4b-4281-b951-d872f2087c98

build/install-build-deps.sh

@@ -91,7 +91,7 @@ if [ "x$(id -u)" != x0 ] && [ 0 -eq "${do_quick_check-0}" ]; then
 fi
 
 # Packages needed for chromeos only
-chromeos_dev_list="libbluetooth-dev"
+chromeos_dev_list="libbluetooth-dev libxkbcommon-dev"
 
 # Packages needed for development
 dev_list="apache2.2-bin bison curl dpkg-dev elfutils devscripts fakeroot flex