Revert "id of iframe incorrectly sets window name"

This CL broke browser_tests in Chromium OS.
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%282%29/builds/22180

TBR=cdumez

Review URL: https://codereview.chromium.org/192643002

git-svn-id: svn://svn.chromium.org/blink/trunk@168829 bbb929c8-8fbe-4397-9dbb-9b2b20218538