The native port callback is now passed the message as a decodes
Dart_CMessage structure. The Dart_CMessage structure is allocated
in a zone and the callback receiving it should expect the
lifetime to be controlled by the caller.
Added support for zones which do not require a current
isolate. Changed the GrowableArray to support allocating in
aprovided zone instead of the zone for the current isolate.
R=turnidge@google.com, asiva@google.com
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com//9325022
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@4068 260f80e4-7a28-3924-810f-c04153c831b5