Start using FocusedNodedChanged to restartInput.

Android requires us to call restart input when input node changes.
Previously we relied on onHandleGesture which is not the right way
to do it.

BUG=242715

Review URL: https://codereview.chromium.org/56643003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245130 0039d316-1c4b-4281-b951-d872f2087c98
Add the UI compositor to the Mac build

Move the bulk of the files in content/browser/aura to
content/browser/compositor, since they're not aura-specific.

Build all of those files in the Mac build, and add ui/compositor
to the dependencies of the Mac build. These files will soon only
be excluded from the Android build.

BUG=314190

Review URL: https://codereview.chromium.org/137893007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245131 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245131