Add DomDistiller.PageDistilledType and update DD.PageDistillableType

Add DomDistiller.PageDistilledType and update DD.PageDistillableType

This adds a new distallable type (mobile-friendly distillable) and adds
a histogram for tracking what types of pages are actually distilled.

BUG=444160
Committed: https://crrev.com/1b6d8e7452e6976532fbf920124788b3e054c5ae
Cr-Commit-Position: refs/heads/master@{#314956}

[cjhopman, 2015-02-04 18:11:48]

cjhopman@chromium.org changed reviewers:
+ isherman@chromium.org

[cjhopman, 2015-02-04 18:15:16]

isherman: *

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (left):

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:5438: -<histogram
name="DomDistiller.PageDistillable" enum="BooleanDistillable">
This histogram previously used UMA_HISTOGRAM_BOOLEAN for recording values and I
guess we would now want to use UMA_HISTOGRAM_ENUMERATION. I don't know if we're
actually allowed to upgrade a histogram in that way or not.

[Ilya Sherman, 2015-02-04 23:08:44]

LGTM.  For future reference, please include UMA changes in the same CL as the
one that implements the code changes to the metrics.  This allows your reviewer
to review the UMA_HISTOGRAM_ macro usage as well, which is actually one of the
most valuable parts of the review.

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (left):

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:5438: -<histogram
name="DomDistiller.PageDistillable" enum="BooleanDistillable">
On 2015/02/04 18:15:16, cjhopman wrote:
> This histogram previously used UMA_HISTOGRAM_BOOLEAN for recording values and
I
> guess we would now want to use UMA_HISTOGRAM_ENUMERATION. I don't know if
we're
> actually allowed to upgrade a histogram in that way or not.

Yes, that's a valid change.  A boolean histogram is essentially an enumerated
histogram with two buckets.

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:5450: +    distillable, etc) for each
distilled page.
It might help to clarify whether "mobile-friendly distillable" is a strict
subset of "distillable", or if "distillable" really means "non-mobile-friendly
distillable".

[cjhopman, 2015-02-06 01:40:07]

New patchsets have been uploaded after l-g-t-m from isherman@chromium.org

[cjhopman, 2015-02-06 01:43:00]

Yeah, I would love to have been able to include the changes to how its recorded
in this review. That code is currently in Chrome for Android's private repo :(
...

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/900963003/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:5450: +    distillable, etc) for each
distilled page.
On 2015/02/04 23:08:44, Ilya Sherman wrote:
> It might help to clarify whether "mobile-friendly distillable" is a strict
> subset of "distillable", or if "distillable" really means "non-mobile-friendly
> distillable".

Done.

[cjhopman, 2015-02-06 01:43:08]

The CQ bit was checked by cjhopman@chromium.org

[commit-bot: I haz the power, 2015-02-06 01:43:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/900963003/20001

[commit-bot: I haz the power, 2015-02-06 03:36:44]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-06 03:39:45]

Patchset 2 (id:??) landed as
https://crrev.com/1b6d8e7452e6976532fbf920124788b3e054c5ae
Cr-Commit-Position: refs/heads/master@{#314956}