add some missing css support

This CL
- defines and allows box-sizing, overflow-wrap, word-wrap.
- fixes some of the background property defs.
- adds 'vmin' and 'vmax' to the units list.

There's a systematic problem with 'inherit' in our css-defs. A lot of
the css spec docs omit 'inherit' in describing individual properties
but have a statement like "All properties defined in this specification
also accept the inherit keyword as their value, but for readability it
has not been listed explicitly."

I've added a few of the missing inherits in this CL, but I haven't
yet tried to systematically add all the missing inherits. I suspect
it might be simpler to implicitly allow all properties to have the
value 'inherit', but I need to verify that's correct and/or safe.

[MikeSamuel, 2013-08-07 17:55:46]

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
File src/com/google/caja/lang/css/css-extensions-defs.json (right):

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:145: "signature": "<box>
[, <box>]* | inherit",
"Inherit" is subsumed by <box> below in this CL and in the www.w3.org version
but not in the dev version.  I'm fine with blanket allowing "inherit" for all
properties, and CSSPropertyPatterns won't suffer from duplicates keywords, but
these spec discrepancies over "inheit"

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:150: "source":
"http://www.w3.org/TR/2009/CR-css3-background-20091217/#the-background-clip",
http://dev.w3.org/csswg/css-backgrounds/#the-background-clip is probably more
up-to-date than 20091217.  Tab Atkinson told me that the www.w3.org versions are
horribly out of date in places and told me to stick to dev.w3.org versions.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:171: "source":
"http://www.w3.org/TR/css3-background/#background-origin",
http://dev.w3.org/csswg/css-backgrounds/#the-background-origin

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:433: "source":
"http://www.w3.org/TR/css3-text/#overflow-wrap" },
Maybe "as": "word-wrap"

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:624: "signature": "normal
| keep-all | break-all | inherit",
I don't think inherit is allowed here.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:630: "source":
"http://www.w3.org/TR/css3-text/#word-break" },
http://dev.w3.org/csswg/css-text/#word-break

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:639: "source":
"http://www.w3.org/TR/css3-text/#word-wrap" },
http://dev.w3.org/csswg/css-text/#word-wrap

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:712: "source":
"http://www.w3.org/TR/css3-background/#background-clip"
http://dev.w3.org/csswg/css-backgrounds/#box differs from this by excluding
"inherit"

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
File src/com/google/caja/lang/css/css21-fns-defs.json (right):

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css21-fns-defs.json:10: { "key": "attr",
"signature": "<ident>
((string|value|url|integer|number|length|angle|time|frequency|em|ex|px|gd|rem|vw|vh|vm|vmin|vmax|mm|cm|in|pt|pc|deg|grad|rad|ms|s|Hz|kHz|percentage)
<value>?)?" },
Hmm.  What is this "attr" thing for?

[felix8a, 2013-08-07 20:03:08]

This CL
- defines and allows box-sizing, overflow-wrap, word-wrap.
- fixes some of the background property defs.
- adds 'vmin' and 'vmax' to the units list.

There's a systematic problem with 'inherit' in our css-defs. A lot of
the css spec docs omit 'inherit' in describing individual properties
but have a statement like "All properties defined in this specification
also accept the inherit keyword as their value, but for readability it
has not been listed explicitly."

I've added a few of the missing inherits in this CL, but I haven't
yet tried to systematically add all the missing inherits. I suspect
it might be simpler to implicitly allow all properties to have the
value 'inherit', but I need to verify that's correct and/or safe.

[felix8a, 2013-08-07 20:03:15]

new snapshot

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
File src/com/google/caja/lang/css/css-extensions-defs.json (right):

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:150: "source":
"http://www.w3.org/TR/2009/CR-css3-background-20091217/#the-background-clip",
On 2013/08/07 17:55:46, MikeSamuel wrote:
> http://dev.w3.org/csswg/css-backgrounds/#the-background-clip is probably more
> up-to-date than 20091217.  Tab Atkinson told me that the http://www.w3.org
versions are
> horribly out of date in places and told me to stick to http://dev.w3.org
versions.

Done.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:171: "source":
"http://www.w3.org/TR/css3-background/#background-origin",
On 2013/08/07 17:55:46, MikeSamuel wrote:
> http://dev.w3.org/csswg/css-backgrounds/#the-background-origin

Done.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:433: "source":
"http://www.w3.org/TR/css3-text/#overflow-wrap" },
On 2013/08/07 17:55:46, MikeSamuel wrote:
> Maybe "as": "word-wrap"

since word-wrap is the deprecated one, I'll do the opposite.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:624: "signature": "normal
| keep-all | break-all | inherit",
On 2013/08/07 17:55:46, MikeSamuel wrote:
> I don't think inherit is allowed here.

it's mentioned here http://dev.w3.org/csswg/css-text/#values

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:630: "source":
"http://www.w3.org/TR/css3-text/#word-break" },
On 2013/08/07 17:55:46, MikeSamuel wrote:
> http://dev.w3.org/csswg/css-text/#word-break

Done.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:639: "source":
"http://www.w3.org/TR/css3-text/#word-wrap" },
On 2013/08/07 17:55:46, MikeSamuel wrote:
> http://dev.w3.org/csswg/css-text/#word-wrap

Done.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css-extensions-defs.json:712: "source":
"http://www.w3.org/TR/css3-background/#background-clip"
On 2013/08/07 17:55:46, MikeSamuel wrote:
> http://dev.w3.org/csswg/css-backgrounds/#box differs from this by excluding
> "inherit"

Done.

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
File src/com/google/caja/lang/css/css21-fns-defs.json (right):

https://codereview.appspot.com/12557045/diff/1/src/com/google/caja/lang/css/c...
src/com/google/caja/lang/css/css21-fns-defs.json:10: { "key": "attr",
"signature": "<ident>
((string|value|url|integer|number|length|angle|time|frequency|em|ex|px|gd|rem|vw|vh|vm|vmin|vmax|mm|cm|in|pt|pc|deg|grad|rad|ms|s|Hz|kHz|percentage)
<value>?)?" },
On 2013/08/07 17:55:46, MikeSamuel wrote:
> Hmm.  What is this "attr" thing for?

oh, it's not what I thought it was. ok, not needed.

[MikeSamuel, 2013-08-07 22:38:26]

LGTM

[felix8a, 2013-08-08 19:10:51]

@r5537