Adding media filters interface definitions.

Adding media filters interface definitions.The scheduler (forward declared and mentioned in comments) will arrive in a later patch.  The buffers are already checked in under media/base/buffers.h

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=6393

[scherkus (not reviewing), 2008-12-04 02:22:20]

Checking in the media filter interface definitions.  We've built some very
successful prototypes based on these interfaces and we're ready to freeze them
(or at least start chilling them).

[Peter Kasting, 2008-12-04 19:01:39]

I'm clueless about this kind of thing but it LGTM.

http://codereview.chromium.org/13116/diff/8/204
File media/base/filters.h (right):

http://codereview.chromium.org/13116/diff/8/204#newcode82
Line 82: virtual int Read(char* data, size_t size) = 0;
Nit: Looks like this should return a size_t?  (If you're uncomfortable with
returning -1 directly on failure, you could define some sort of error constant
as -1 [the way the STL does with npos]).

[scherkus (not reviewing), 2008-12-04 19:38:02]

Updated the definition of DataSourceInterface::Read to return size_t and an
error constant.

http://codereview.chromium.org/13116/diff/8/204
File media/base/filters.h (right):

http://codereview.chromium.org/13116/diff/8/204#newcode82
Line 82: virtual int Read(char* data, size_t size) = 0;
On 2008/12/04 19:01:39, pkasting wrote:
> Nit: Looks like this should return a size_t?  (If you're uncomfortable with
> returning -1 directly on failure, you could define some sort of error constant
> as -1 [the way the STL does with npos]).

Good suggestion.  I'll use the -1 representation of size_t, which is the maximum
possible value of size_t.