Pepper/Flapper: Add IsFormatAvailable() to PPB_Flash_Clipboard.

Pepper/Flapper: Add IsFormatAvailable() to PPB_Flash_Clipboard.

This requires a WebKit change (see
https://bugs.webkit.org/show_bug.cgi?id=56868).

BUG=none
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=79289

[brettw, 2011-03-23 02:18:12]

Isn't there a race condition here? If Flash is running asynchronously, couldn't
the contents and type of the clipboard change between the call to "is valid" and
getting the actual contents? It seems like we should have a function to request
the contents in one fell swoop. I'm not sure about the exact requirements, but
maybe there could be a flag for "prefer HTML" to control whether you get HTML if
it's available, or just get plain text.

[vtl, 2011-03-23 03:41:35]

Such functions always have a race condition (even without async --
since some other program may modify the clipboard), and functions to
get clipboard data must always be able to deal with not getting the
data they requested.

Querying whether a format is available is meant to allow UI to reflect
the clipboard state (e.g., disable/enable a Paste menu item).

On Tue, Mar 22, 2011 at 19:18,  <brettw@chromium.org> wrote:
> Isn't there a race condition here? If Flash is running asynchronously,
> couldn't
> the contents and type of the clipboard change between the call to "is valid"
> and
> getting the actual contents? It seems like we should have a function to
> request
> the contents in one fell swoop. I'm not sure about the exact requirements,
> but
> maybe there could be a flag for "prefer HTML" to control whether you get
> HTML if
> it's available, or just get plain text.
>
> http://codereview.chromium.org/6724010/
>

[brettw, 2011-03-23 16:00:04]

Okay, I was worried that the use case was more like
  if (isHTMLAvailable())
    getHTMLClipboardData();
but your use case sounds correct.

LGTM.