Move test_file_set to content/test/

BUG=338338
TBR=darin@chromium.org

Review URL: https://codereview.chromium.org/183343002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254816 0039d316-1c4b-4281-b951-d872f2087c98
Added ygorshenin@chromium.org to OWNERS.

BUG=none
TEST=none

Review URL: https://codereview.chromium.org/177443005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254817 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254816
MTP Streaming: Optimize header verification.

Currently, for MTP streaming, we make a special request for the header bytes, to verify that it is indeed a media file.

In the common case of reading from start to finish, this is wasteful, as the originally requested read starts from the 0th byte and includes the header bytes anyways.

This detects that case, and reads the first chunk directly, and then looks at the header bytes within that.

BUG=110119

Review URL: https://codereview.chromium.org/185593008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254818 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254818