track count of prefixed properties that are imported

track count of prefixed properties that are imported

It would be nice if we didn't have to add -webkit- to any of the css
properties used in the w3c tests. This changes adds some summary statistics
to the import so we can track which ones to unprefix first.

R=ojan@chromium.org
BUG=242738
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=151130

[ojan, 2013-05-22 00:20:51]

lgtm

no tests?

[Dirk Pranke, 2013-05-22 00:26:18]

On 2013/05/22 00:20:51, ojan wrote:
> lgtm
> 
> no tests?

Adding tests seemed like more trouble than it was worth, but I'll take another
look.

[Dirk Pranke, 2013-05-24 20:25:02]

On 2013/05/22 00:26:18, Dirk Pranke wrote:
> On 2013/05/22 00:20:51, ojan wrote:
> > lgtm
> > 
> > no tests?
> 
> Adding tests seemed like more trouble than it was worth, but I'll take another
> look.

I need to rework all of the test code to use a MockFilesystem; before that, it's
quite difficult to test this usefully, so I'll punt on that for now (I already
have a fixme for this).

[Dirk Pranke, 2013-05-24 20:25:30]

Committed patchset #1 manually as r151130 (presubmit successful).