e8f396df7e
This change adds peer and callback arguments to the external byte array constructor and moves the peer, callback, and data storage into a VM peer object. At construction time, a weak persistent handle and VM callback is associated with the VM peer. The VM callback will delete the VM peer and invokes the user callback to reclaim the user peer. This change also activates the callback support for the various classes of external strings. Review URL: https://chromiumcodereview.appspot.com//9368049 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@4164 260f80e4-7a28-3924-810f-c04153c831b5