[webcrypto] Move the files to a subdirectory (content/renderer/webcrypto).

BUG=245025
R=jamesr@chromium.org, jochen@chromium.org

Review URL: https://codereview.chromium.org/24494003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225659 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225659
Support clear buffer in encrypted stream in MediaDecoderJob.

BUG=298483
TEST=Clear start in an encrypted stream plays with Widevine:
http://dash-mse-test.appspot.com/dash-player.html

Review URL: https://codereview.chromium.org/24752003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225660 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225660