HID API frontend for Apps.

This issue is a continuation of https://codereview.chromium.org/145653003/ with some cleanup to reflect conventions adopted by other I/O APIs.

BUG=290428

Review URL: https://codereview.chromium.org/149163006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248366 0039d316-1c4b-4281-b951-d872f2087c98
Move the rest of webkit/glue into content/child

One more step towards removing src/webkit/

BUG=265753
TEST=content_shell and content_unittests
R=jochen@chromium.org,jam@chromium.org
TBR=darin

Review URL: https://codereview.chromium.org/151023002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248367 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248367