Make UI strings consistent in the 2nd person - crbug.com/156975

BUG=156975

Review URL: https://codereview.chromium.org/145683002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250094 0039d316-1c4b-4281-b951-d872f2087c98
Add UTF-8 validation of Text frames.

Also relax the validation of the payload of Close frames to permit
non-character codepoints, matching previous behaviour and other
browsers.

BUG=327613
TEST=net_unittests --gtest_filter=WebSocketChannel*

Review URL: https://codereview.chromium.org/157273004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250095 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250095