GN: Exclude symbolize, xdg_mime and xdg_user_dirs on Android

Following current GYP rules, exclude these dependencies on Android.

This causes a downstream break for the WebView build which must exclude
xdg_mime for licensing reasons.

Review URL: https://codereview.chromium.org/106013005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243001 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243001
[ToolBar] Enable RTL flipping for back, forward, home, reload buttons.

R=msw@chromium.org
BUG=330911

Review URL: https://codereview.chromium.org/123343003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243002 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243002