Add lcd_density to StartArcMiniContainerRequest This will be used to inject the density from chrome to Android. BUG=b:66995734 TEST=manual Change-Id: I4cc7e1387389e1cb5c7e099584c12763ed1c5988 Reviewed-on: https://chromium-review.googlesource.com/1197393 Commit-Ready: Mitsuru Oshima <[email protected]> Tested-by: Mitsuru Oshima <[email protected]> Reviewed-by: Yusuke Sato <[email protected]>