Remove unused Pepper FileSystem IPC message.

BUG=194304

Review URL: https://chromiumcodereview.appspot.com/24395003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224948 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224948
Delete automation code needed by old (and deleted) ChromeDriver.
BUG=none

Review URL: https://chromiumcodereview.appspot.com/24396002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224949 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224949