Move ExtractJWKKeys to json_web_key

Cleanup to move JWK functionality into one file. Also require that base64 padding characters are not present.

BUG=303381
TEST=media_unittests pass

Review URL: https://codereview.chromium.org/83593004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237517 0039d316-1c4b-4281-b951-d872f2087c98
Extract CreateInitProcessReaper() from the Zygote.

CreateInitProcessReaper() is useful for the CLONE_NEWUSER-based
sandbox as well as for the current Zygote. Extract it so that it
can be used independantly of content/.

CreateInitProcessReaper() is now exposed to content through the
setuid sandbox client.

BUG=312380

Review URL: https://codereview.chromium.org/90243002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237518 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237518
[SyncFS] Dirty tracker accessor should be optional

BUG=240165
NOTRY=true

Review URL: https://codereview.chromium.org/90653002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237519 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237519