Update ClearKeyCdm to use CDM_3.

Chrome now supports CDM_3, so update the ClearKeyCdm implementation to use the new interface.

BUG=224786
TEST=encrypted-media layout tests and browser_tests for encrypted media pass

Review URL: https://codereview.chromium.org/102503002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241759 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241759
Move chrome/browser/net/chrome_network_data_saving_metrics.* to chrome/browser/net/spdyproxy/ where other data reduction stuff lives now.

BUG=328605

Review URL: https://codereview.chromium.org/112923004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241760 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241760