login_manager: Enable accelerated 2d canvas on link
login_manager: Enable accelerated 2d canvas on link

For testing and dogfooding it is easier to have a build with the
accelerated 2d canvas enabled, rather than hacking the image.

BUG=chromium-os:34278
TEST=trybots: amd64 and arm paladins, link-release

Change-Id: I9faf24b4b542fb35edc6e1b80b2d0c9fe2874072
Reviewed-on: https://gerrit.chromium.org/gerrit/32798
Reviewed-by: Chris Masone <98e3d65c6b0e9e2391eb4c2e8b1e572b77e544ed@chromium.org>
Commit-Ready: Chris Wolfe <4f23406e03c8ffaccefe8744212d3543c02e8d87@chromium.org>
Tested-by: Chris Wolfe <4f23406e03c8ffaccefe8744212d3543c02e8d87@chromium.org>

chadversary/chromiumos.platform.login_manager,chadversary/chromiumos.platform.login_manager,chadversary/chromiumos.platform.login_manager