restore old convention of asserting refcnt==1 in destructor

BUG=skia:

Review URL: https://codereview.chromium.org/757563003
Revert of Blink hasn't rolled yet. (patchset #1 id:1 of https://codereview.chromium.org/754133002/)

Reason for revert:
Not thorough enough.

Original issue's description:
> Blink hasn't rolled yet.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/fa14113d0563686af9f7e2d8e041dd7bf538cfa2

TBR=mtklein@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/752303002
Blink hasn't rolled yet, better.

BUG=skia:

Review URL: https://codereview.chromium.org/758693002
option to return drawable from recording

patch from issue 747033005 at patchset 80001 (http://crrev.com/747033005#ps80001)

BUG=skia:

Review URL: https://codereview.chromium.org/732653004
Don't count a leading 1 as a signficant digit in the ratio.

What used to look like this:
            desk_pokemonwiki.skp    9.38ms -> 9.76ms    1x
                 tabl_pravda.skp     237us ->  241us    1x
          desk_css3gradients.skp     249us ->  254us    1x
            ....
               desk_fontwipe.skp    39.6us -> 38.7us    0.98x
                   tabl_digg.skp     922us ->  893us    0.97x
                  tabl_gmail.skp    20.7us ->   20us    0.96x

Now will print more like this:

            desk_pokemonwiki.skp    9.38ms -> 9.76ms    1.04x
                 tabl_pravda.skp     237us ->  241us    1.02x
          desk_css3gradients.skp     249us ->  254us    1.02x
            ....
               desk_fontwipe.skp    39.6us -> 38.7us    0.98x
                   tabl_digg.skp     922us ->  893us    0.97x
                  tabl_gmail.skp    20.7us ->   20us    0.96x

BUG=skia:

Review URL: https://codereview.chromium.org/756643004
SkRecord: outline methods that are not called O(N) times.

Looks like a noop-to-minor-win:
                tabl_sahadan.skp	94.9us -> 98.6us	1x
         desk_jsfiddlebigcar.skp	38.9us -> 39.7us	1x
            desk_silkfinance.skp	  78us -> 78.9us	1x
     desk_jsfiddlehumperclip.skp	43.8us -> 44.3us	1x
                 desk_sfgate.skp	 547us ->  548us	1x
                  tabl_gmail.skp	19.9us -> 19.8us	1x
           tabl_worldjournal.skp	 230us ->  229us	1x
          desk_css3gradients.skp	 248us ->  247us	1x
                    tabl_cnn.skp	 205us ->  203us	0.99x
               desk_linkedin.skp	 342us ->  340us	0.99x
                desk_wowwiki.skp	1.63ms -> 1.62ms	0.99x
                   tabl_cnet.skp	 142us ->  141us	0.99x
            desk_pokemonwiki.skp	9.76ms -> 9.67ms	0.99x
                   desk_espn.skp	 267us ->  264us	0.99x
                desk_youtube.skp	 576us ->  570us	0.99x
                 tabl_pravda.skp	 238us ->  235us	0.99x
                  tabl_ukwsj.skp	 566us ->  560us	0.99x
               tabl_engadget.skp	 630us ->  622us	0.99x
desk_googlespreadsheetdashed.skp	1.66ms -> 1.64ms	0.99x
             desk_mobilenews.skp	 486us ->  480us	0.99x
         tabl_googlecalendar.skp	 211us ->  208us	0.99x
               desk_samoasvg.skp	 740us ->  730us	0.99x
                    desk_gws.skp	 187us ->  184us	0.99x
                   desk_ebay.skp	 234us ->  230us	0.99x
                 desk_mapsvg.skp	 1.6ms -> 1.58ms	0.98x
                tabl_nytimes.skp	 130us ->  128us	0.98x
             tabl_googleblog.skp	 305us ->  300us	0.98x
               desk_fontwipe.skp	40.3us -> 39.6us	0.98x
               desk_tigersvg.skp	 189us ->  186us	0.98x
          tabl_androidpolice.skp	 662us ->  650us	0.98x
              desk_wordpress.skp	 824us ->  809us	0.98x
                    tabl_mlb.skp	 338us ->  331us	0.98x
      tabl_culturalsolutions.skp	 390us ->  382us	0.98x
                  desk_baidu.skp	 213us ->  208us	0.98x
                  tabl_gspro.skp	72.9us -> 71.1us	0.97x
                 tabl_nofolo.skp	  74us -> 71.9us	0.97x
           desk_yahooanswers.skp	 173us ->  168us	0.97x
               tabl_frantzen.skp	57.3us -> 55.6us	0.97x
             desk_chalkboard.skp	 891us ->  865us	0.97x
              desk_pinterest.skp	 154us ->  149us	0.97x
                desk_blogger.skp	 537us ->  519us	0.97x
                   tabl_hsfi.skp	10.1us -> 9.69us	0.96x
            desk_gmailthread.skp	 333us ->  318us	0.96x
                   tabl_digg.skp	 926us ->  883us	0.95x
      desk_googlespreadsheet.skp	 586us ->  558us	0.95x
             desk_forecastio.skp	 101us -> 95.7us	0.95x
                desk_booking.skp	 1.1ms -> 1.04ms	0.95x
             tabl_deviantart.skp	 144us ->  136us	0.95x
               desk_facebook.skp	 584us ->  553us	0.95x
                desk_weather.skp	 289us ->  272us	0.94x
             desk_googlehome.skp	61.1us -> 57.5us	0.94x
             desk_googleplus.skp	 914us ->  849us	0.93x
                desk_twitter.skp	 499us ->  463us	0.93x

BUG=skia:

Review URL: https://codereview.chromium.org/756783002