GitLab

Use this implementation for mojo native_viewport. It will also be used for
aura WindowTreeHost in subsequent patches.

BUG=none
R=ben@chromium.org

Review URL: https://codereview.chromium.org/405813002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284752 0039d316-1c4b-4281-b951-d872f2087c98