Added function to implement Coded Frame Eviction Algorithm

Added function to implement Coded Frame Eviction Algorithm

Provided interface to allow blink to implement "3.5.12 Coded
Frame Eviction Algorithm"
https://w3c.github.io/media-source/#sourcebuffer-coded-frame-eviction

Also allowed this function to detect when buffer is overfull,
and throw QUOTA_EXCEEDED_ERR accordingly.
https://w3c.github.io/media-source/#sourcebuffer-prepare-append

[kjoswiak, 2014-12-09 22:59:07]

Codependent on https://codereview.chromium.org/789983003/ (is there a way to
merge these CLs under a single issue? Not sure how for separate repos)

Also WIP. The current garbage collection system is way too aggressive to fail,
so the throwing of the QuotaExceededError cannot presently happen. I would like
https://codereview.chromium.org/791723003 to be implemented first, and will
merge into this change. I also intend to create a unit test once this happens,
to ensure garbage collection behaves reasonably.

For now, mainly want to put this change out there to see if this is a reasonable
way to approach restructuring the garbage collection system.

[kjoswiak, 2014-12-09 23:28:09]

kjoswiak@chromium.org changed reviewers:
+ dalecurtis@chromium.org, wolenetz@chromium.org

[kjoswiak, 2014-12-09 23:28:10]

+dalecurtis, wolenetz

Please add anyone else who would be interested, and let me know who from blink
this is most relevant to.

[philipj_slow, 2014-12-10 09:28:26]

philipj@opera.com changed reviewers:
+ philipj@opera.com

[philipj_slow, 2014-12-10 09:28:26]

This looks reasonable. Please add some LayoutTests that trigger each of the
exceptions. If they're impossible to trigger, we shouldn't have this code :)

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
File Source/modules/mediasource/SourceBuffer.cpp (right):

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
Source/modules/mediasource/SourceBuffer.cpp:518: //  5. If the buffer full flag
equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.
I see that we don't have an explicit "buffer full flag" in Chromium or Blink.
That would have made this code more like the spec, but I guess that's OK.

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
Source/modules/mediasource/SourceBuffer.cpp:519:
exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is full,
and cannot free space append additional buffers.");
missing "to"

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
Source/modules/mediasource/SourceBuffer.cpp:650: // TODO(kjoswiak): Is this
accurate? Are we actually appending data, or appending a data source?
No TODO(user) in Blink, just FIXME. Even better, investigate it and remove the
comment :)

[philipj_slow, 2014-12-10 09:28:57]

Also either remove BUG= or link both CLs to a common bug.

[DaleCurtis, 2014-12-10 18:43:34]

dalecurtis@chromium.org changed reviewers:
- dalecurtis@chromium.org

[kjoswiak, 2014-12-10 19:11:45]

Working on layout tests

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
File Source/modules/mediasource/SourceBuffer.cpp (right):

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
Source/modules/mediasource/SourceBuffer.cpp:518: //  5. If the buffer full flag
equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.
On 2014/12/10 09:28:26, philipj wrote:
> I see that we don't have an explicit "buffer full flag" in Chromium or Blink.
> That would have made this code more like the spec, but I guess that's OK.

Though other thing I considered doing is adding a separate function that just
queried the buffer, asking if its full, instead of relying on this new functions
return value. It felt a little redundant though, so I left it out.

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
Source/modules/mediasource/SourceBuffer.cpp:519:
exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is full,
and cannot free space append additional buffers.");
On 2014/12/10 09:28:26, philipj wrote:
> missing "to"

Done.

https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
Source/modules/mediasource/SourceBuffer.cpp:650: // TODO(kjoswiak): Is this
accurate? Are we actually appending data, or appending a data source?
On 2014/12/10 09:28:26, philipj wrote:
> No TODO(user) in Blink, just FIXME. Even better, investigate it and remove the
> comment :)

whoops meant to remove this, I had actually come to a decision about it,
specifically that since MSE says to run prepare append and this is in the spec
for prepare append its probably best to just leave it in. Done.

[servolk, 2015-03-17 00:04:16]

On 2014/12/10 19:11:45, kjoswiak wrote:
> Working on layout tests
> 
>
https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
> File Source/modules/mediasource/SourceBuffer.cpp (right):
> 
>
https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
> Source/modules/mediasource/SourceBuffer.cpp:518: //  5. If the buffer full
flag
> equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.
> On 2014/12/10 09:28:26, philipj wrote:
> > I see that we don't have an explicit "buffer full flag" in Chromium or
Blink.
> > That would have made this code more like the spec, but I guess that's OK.
> 
> Though other thing I considered doing is adding a separate function that just
> queried the buffer, asking if its full, instead of relying on this new
functions
> return value. It felt a little redundant though, so I left it out.
> 
>
https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
> Source/modules/mediasource/SourceBuffer.cpp:519:
> exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is
full,
> and cannot free space append additional buffers.");
> On 2014/12/10 09:28:26, philipj wrote:
> > missing "to"
> 
> Done.
> 
>
https://codereview.chromium.org/785343002/diff/1/Source/modules/mediasource/S...
> Source/modules/mediasource/SourceBuffer.cpp:650: // TODO(kjoswiak): Is this
> accurate? Are we actually appending data, or appending a data source?
> On 2014/12/10 09:28:26, philipj wrote:
> > No TODO(user) in Blink, just FIXME. Even better, investigate it and remove
the
> > comment :)
> 
> whoops meant to remove this, I had actually come to a decision about it,
> specifically that since MSE says to run prepare append and this is in the spec
> for prepare append its probably best to just leave it in. Done.

Kyle has left Google, continuing this work as a separate CL:
https://codereview.chromium.org/1013923002/