[HarfBuzz] hb_blob_try_writable leaks memory?

[Jonathan Kew]

Hi Behdad,

It looks to me like hb_blob_try_writable() will cause a memory leak if it copies read-only data into a newly allocated block in order to make it writable; I don't see how the block that is malloced in this function would ever be freed.

One way to handle this would presumably be with a private destroy function that is set on the blob when this reallocation takes place; or do you have an alternative suggestion?

Jonathan