Add UseCounter value for HTMLAppletElement and UTF16AsWebExposedEncoding

Add UseCounter value for HTMLAppletElement and UTF16AsWebExposedEncoding

Corresponds to https://codereview.chromium.org/183893021.

R=jsbell@chromium.org
BUG=

[mathiasb, 2014-03-04 15:46:01]

Note that I had to add `HTMLAppletElement` too, as it was still missing.

[jsbell, 2014-03-04 17:01:19]

I'm not an OWNER and can't speak to whether this will give enough data.

It'd also be nice to land the histogram in the same CL as the use of it.

[mathiasb, 2014-03-04 17:09:26]

On 2014/03/04 17:01:19, jsbell wrote:
> It'd also be nice to land the histogram in the same CL as the use of it.

Is that even possible? The UseCounter is added in Blink, but the histograms data
is part of the Chromium repository.

[jsbell, 2014-03-04 17:14:40]

On 2014/03/04 17:09:26, mathiasb wrote:
> On 2014/03/04 17:01:19, jsbell wrote:
> > It'd also be nice to land the histogram in the same CL as the use of it.
> 
> Is that even possible? The UseCounter is added in Blink, but the histograms
data
> is part of the Chromium repository.

Whoops, sorry. I've been in working Chromium-land for a while now. :(

My bad, carry on.

[Ilya Sherman, 2014-03-04 22:46:31]

LGTM

[jsbell, 2014-04-11 15:56:59]

Is there still desire to pursue this (given that we have other ways go gather
stats about encoding usage), or can we close this?

(Just tidying my "Incoming Reviews" list)

[Ilya Sherman, 2014-04-11 22:56:45]

If you've already committed the C++ code that emits to this histogram, then you
should update the enum in histograms.xml, regardless of whether you later decide
to use a different mechanism to analyze the data.  Once there's C++ code that
emits to them, the buckets are reserved, and should not be possible to re-use
for any other logging purposes.  It's fine to deprecate them and stop emitting
to them entirely, but even in that case, the histograms.xml enum should be kept
up-to-date.

[mathiasb, 2014-04-14 08:33:10]

On 2014/04/11 15:56:59, jsbell wrote:
> Is there still desire to pursue this (given that we have other ways go gather
> stats about encoding usage), or can we close this?

I’m fine with closing this, but it would be nice if “UTF-16 as a Web-exposed
encoding” gets tracked somehow (if not through this patch, through the “other
means” you mentioned, whatever they are).

[jsbell, 2015-03-13 20:51:37]

"other means" are mentioned in comment #8 over in
https://codereview.chromium.org/183893021/ (with data circa 2013) - we can use
the crawl stats from a (*cough*) large search engine. This misses out on
intranets, but then so may UMA stats.

Gonna close this out.