Revert 234855 "Encrypt all stored cookies on selected operating ..."

[Failed content_unittests on ASAN.]

> Encrypt all stored cookies on selected operating systems.
> 
> As part of the goal of protecting private user information, this encrypts the cookie values on operating systems with user-specific crypto APIs and that do not otherwise protect this data.
> 
> Performance tests indicate a penalty of about 1ms per cookie  (regardless of size) on a Mac and 0.1ms to 0.7ms (depending on the size) under Windows.  This will be higher on older hardware but still insignificant.
> 
> Encrypted data is binary (with an overhead of 128 bytes on Windows) and binary data must be stored in a BLOB so only one of two fields ("value" or "encrypted_value") will have data with the other being empty.  Both values, however, need to be read & written when accessing a cookie because they are marked "non null").
> 
> BUG=313323
> 
> Review URL: https://codereview.chromium.org/24734007

TBR=bcwhite@chromium.org

Review URL: https://codereview.chromium.org/70913003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234873 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234873