cc: don't lose resources sent to parent when ResourceProvider::Child is destroyed.

Since we recreate the DelegatedRendererLayer in some cases (e.g. child changed,
size changed), we'll delete the Child, but we don't want to lose resources that
may be in the parent. Instead we can delay the Child destruction until all
resources have been returned (or we destroy the ResourceProvider).

BUG=315847

Review URL: https://codereview.chromium.org/66803006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234712 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234712
Reland 234430 "kiosk: Remove cryptohome migration code."

BUG=265506

Review URL: https://codereview.chromium.org/69333003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234713 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234713