Clean up base/Version

Clean up base/Version

It turns out base/Version is really a value object but probably because of some serious accident or by
the machinations of a super villain, forgot his identity and now it thinks is a reference object,
only creatable in the heap and that could only spawn offsprings via cloning.

But fear not 'cause I've seen Version true nature; At its core is just a good 'ol vector<uint16>, which has
very respectable value semantics. Also I have removed the is_valid_ parasite as much as I could.

The old interface (GetVersionFromString and Clone) is kept so existing callers would not need to be modified.

BUG=none
TEST=included
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=88143

[brettw, 2011-06-01 07:28:17]

I don't really get this. Why not just make a Version(std::string) and have no
default constructor?

[cpu_(ooo_6.6-7.5), 2011-06-01 21:07:06]

On 2011/06/01 07:28:17, brettw wrote:
> I don't really get this. Why not just make a Version(std::string) and have no
> default constructor?

I think some code has a std::vector<Version>, I did not care to look where the
code is. That is what the header said.

[brettw, 2011-06-02 08:34:31]

Can't you put something in a vector that doesn't have a default constructor? I'd
rather figure this out, the API in this patch seems weird to me.

[cpu_(ooo_6.6-7.5), 2011-06-06 22:18:24]

On 2011/06/02 08:34:31, brettw wrote:
> Can't you put something in a vector that doesn't have a default constructor?
I'd

Yes, you can, I was just repeating what the header (version.h) said, if I look
at actual usages I see it used as a member variable on some objects like in
extensions\extension_sync_data.cc

It seems convenient to have an uninitialized Version object, just like a GURL.


> rather figure this out, the API in this patch seems weird to me.

My updated patch adds the regular c++ value functionality including ctor from
string. 

The only thing left (for some other CL) I think is to remove the two functions
that are marked "do not use" and convert the callers.

[Evan Martin, 2011-06-06 23:35:13]

http://codereview.chromium.org/7105008/diff/6001/base/version.cc
File base/version.cc (right):

http://codereview.chromium.org/7105008/diff/6001/base/version.cc#newcode21
base/version.cc:21: // TODO: remove this method.
TODO(cpu) or file a bug :)

http://codereview.chromium.org/7105008/diff/6001/base/version.h
File base/version.h (right):

http://codereview.chromium.org/7105008/diff/6001/base/version.h#newcode25
base/version.h:25: // for constraints on the inputs.
What happens to the return value of InitFromString()?
I feel like we should deprecate this function as well.

http://codereview.chromium.org/7105008/diff/6001/base/version.h#newcode34
base/version.h:34: // propper format. Caller is responsible for freeing the
Version
Typo: maybe meant a period before capitalized "Returns"?
Typo: "proper"

[cpu_(ooo_6.6-7.5), 2011-06-07 00:55:05]

All changes made. Please look again.

[Evan Martin, 2011-06-07 03:06:26]

LGTM