Change ContentLinker to share relro sections with browser process only on low-end devices.

While this change increases memory usage on non low-end devices, the
impact is small enough that we can limit the exposure surface to only
where it makes a signficant impact.

Also adds content_linker_test_apk to the android builders to ensure it
doesn't regress.

Review URL: https://codereview.chromium.org/139743011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247622 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247622
Skeleton of a View Manager.

This CL doesn't add any real View Management nor does it convert any apps to use this API. Mostly this is just getting the target in and doing the event interception to load the Launcher.

R=sky@chromium.org
BUG=

Review URL: https://codereview.chromium.org/145403002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247623 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247623