Implement "Copy image" for canvas (chromium side).

Implement "Copy image" for canvas (chromium side).

Many users want to copy the image of <canvas> to clipboard. (like <img>)
As well as being useful, The feature is already supported in Firefox and IE.

Blink side:
  https://codereview.chromium.org/270613004/

BUG=369092
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281470

[zino, 2014-05-09 09:30:54]

Please take a look.

Thank you :)

[Justin Novosad, 2014-05-09 14:25:26]

On 2014/05/09 09:30:54, zino wrote:
> Please take a look.
> 
> Thank you :)

That's it?  If I understand correctly, this will just retrieve the image as a
data URL through the same IPC that image tagsuse?

I'm not an owner, but this looks great! Thanks

[Avi (use Gerrit), 2014-05-09 15:09:20]

Huh. So all the stuff you put in already handles it? Well, what's to complain
about? LGTM

[zino, 2014-05-09 17:14:07]

On 2014/05/09 14:25:26, junov wrote:
> On 2014/05/09 09:30:54, zino wrote:
> > Please take a look.
> > 
> > Thank you :)
> 
> That's it?  If I understand correctly, this will just retrieve the image as a
> data URL through the same IPC that image tagsuse?

Yes, we can use the same content API (and IPC as well) that image tag use.
But I don't think we need data URL in this case. Instead we can copy the image
directly.
A case of save image, we couldn't help using a data URL because the download
manager requires it in order to save as file.

As a result, I just extended copyImage() to be able to support canvas in Blink
side.
So, it is very simple in chromium side

Thank you :)

[zino, 2014-07-03 10:46:43]

@Avi,

This CL has already gotten lgtm but it haven't been landed for a long time.
I already finished rebase. So, can I commit this?

[Avi (use Gerrit), 2014-07-03 15:23:08]

On 2014/07/03 10:46:43, zino wrote:
> @Avi,
> 
> This CL has already gotten lgtm but it haven't been landed for a long time.
> I already finished rebase. So, can I commit this?

When I gave you the LG I expected that you would commit it. I'm surprised that
you haven't yet.

[zino, 2014-07-05 03:02:30]

The CQ bit was checked by jinho.bang@samsung.com

[commit-bot: I haz the power, 2014-07-05 03:03:23]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jinho.bang@samsung.com/275833002/20001

[zino, 2014-07-05 17:50:03]

The CQ bit was unchecked by jinho.bang@samsung.com

[zino, 2014-07-05 17:50:04]

The CQ bit was checked by jinho.bang@samsung.com

[commit-bot: I haz the power, 2014-07-05 17:50:26]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jinho.bang@samsung.com/275833002/20001

[commit-bot: I haz the power, 2014-07-05 19:10:59]

Change committed as 281470