Remove the ability to allow multiple gc prologue and gc epilogue callbacks

Remove the ability to allow multiple gc prologue and gc epilogue callbacks
to be registered at any given time. Dartium seems to use only one.

R=iposva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=33622

[Ivan Posva, 2014-03-12 21:06:41]

LGTM -ip

https://codereview.chromium.org/197963002/diff/1/runtime/vm/dart_api_impl.cc
File runtime/vm/dart_api_impl.cc (right):

https://codereview.chromium.org/197963002/diff/1/runtime/vm/dart_api_impl.cc#...
runtime/vm/dart_api_impl.cc:767: DART_EXPORT Dart_Handle
Dart_AddGcPrologueCallback(
We might want to follow the other functions in the API here and use a
Dart_SetGcPrologueCallback() instead of add and remove, where removal is
equivalent to setting a NULL callback. Or since these callback really function
in pairs maybe even just have a single Dart_SetGcCallback()?

To make it easier to roll this change, it is probably OK to have both versions
for a brief period.

https://codereview.chromium.org/197963002/diff/1/runtime/vm/dart_api_impl.cc#...
runtime/vm/dart_api_impl.cc:820: "%s expects 'callback' to be present in the
epilogue callback list.",
Still referencing list.

[siva, 2014-03-12 22:38:53]

https://codereview.chromium.org/197963002/diff/1/runtime/vm/dart_api_impl.cc
File runtime/vm/dart_api_impl.cc (right):

https://codereview.chromium.org/197963002/diff/1/runtime/vm/dart_api_impl.cc#...
runtime/vm/dart_api_impl.cc:767: DART_EXPORT Dart_Handle
Dart_AddGcPrologueCallback(
Done, Added Dart_SetGcCallbacks(prologue, epilogue);

The old API is still around until I can remove it's usage from Dartium.

On 2014/03/12 21:06:41, Ivan Posva wrote:
> We might want to follow the other functions in the API here and use a
> Dart_SetGcPrologueCallback() instead of add and remove, where removal is
> equivalent to setting a NULL callback. Or since these callback really function
> in pairs maybe even just have a single Dart_SetGcCallback()?
> 
> To make it easier to roll this change, it is probably OK to have both versions
> for a brief period.

https://codereview.chromium.org/197963002/diff/1/runtime/vm/dart_api_impl.cc#...
runtime/vm/dart_api_impl.cc:820: "%s expects 'callback' to be present in the
epilogue callback list.",
On 2014/03/12 21:06:41, Ivan Posva wrote:
> Still referencing list.

Done.

[siva, 2014-03-12 22:39:20]

Committed patchset #3 manually as r33622 (presubmit successful).