[Android] Fix overflow menu enter tablet animation

[Android] Fix overflow menu enter tablet animation

- On tablets the new anchor point was 6dp off due to the new shadow assets.  To fix
this add a 6dp translate to the enter animation that will move the asset into the
correct location as the scale animation runs.  This effectively mimics the old
animation but allows the offset to be included.

BUG=405352
Review URL: https://codereview.chromium.org/488863002

Cr-Commit-Position: refs/heads/master@{#290773}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@290773 0039d316-1c4b-4281-b951-d872f2087c98
(cherry picked from commit 6f2a9c8524cf5a0e92bffeb63550be0321bacfbb)

Committed: https://chromium.googlesource.com/chromium/src/+/b1838a4e4c2d0a1b9ca78d3f40ee33bcbf0670b5

[David Trainor- moved to gerrit, 2014-09-02 19:00:08]

Committed patchset #1 (id:1) manually as b1838a4.