Forms: improve cpp/c interface regarding exceptions

Three alterations:
We were previously being careful to avoid throwing exceptions in
the DOM-implementation callbacks because these were being called
directly from C++. This commit adds three veneers that turn exceptions
into warnings, hence allowing the callbacks to be written in usual
mupdf style.

Protect the "field" callbacks from executing with a NULL field.

Ensure that the event object is set up before executing A actions

0 files changed, 0 insertions, 0 deletions