Add UseCounters for the types of mixed content we currently don't block.

Add UseCounters for the types of mixed content we currently don't block.

In order to evaluate when we can start dropping support for passive
mixed content, this patch adds counters to ResourceFetcher for the four
resource types we currently don't block: images, media, tracks, and raw.
This patch also drops the 'MixedContentFont' enum, as we now consider
that active content.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175557

[Mike West, 2014-06-05 06:54:31]

Mind taking a look?

-mike

[jochen (gone - plz use gerrit), 2014-06-05 07:01:05]

lgtm

[Mike West, 2014-06-05 07:24:10]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2014-06-05 07:25:15]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mkwst@chromium.org/312253003/1

[commit-bot: I haz the power, 2014-06-05 08:34:24]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/10744)

[commit-bot: I haz the power, 2014-06-05 11:26:50]

Change committed as 175557