dart2js CPS: Support try/catch/finally.

dart2js CPS: Support try/catch/finally.

Support try/catch/finally by pretending it is macro-expanded into
try/catch and try/finally:

    try S0 catch (ex, st) S1 finally S2
    ==>
    try { try S0 catch (ex, st) S1 } finally S2

The duplicated code for try/catch and try/finally is abstracted into a
function parameterized over translations for all the parts that
differed.

R=asgerf@google.com

Committed: https://github.com/dart-lang/sdk/commit/b9192ab9e283a3ab6dc64d3467cd4a5741e3673b

[Kevin Millikin (Google), 2015-06-24 13:19:33]

kmillikin@google.com changed reviewers:
+ asgerf@google.com

[asgerf, 2015-06-24 14:11:16]

Can't we have buildTryCatch and a buildTryFinally on the builder and then have
the visitor call those? I think it would simplify it a lot.

[Kevin Millikin (Google), 2015-06-24 15:02:08]

It helps a little by keeping things a bit more encapsulated.  Otherwise it just
moves code around.

What do you think?

[asgerf, 2015-06-24 15:06:58]

Thanks, LGTM.

[Kevin Millikin (Google), 2015-06-24 15:13:33]

Committed patchset #3 (id:40001) manually as
b9192ab9e283a3ab6dc64d3467cd4a5741e3673b (presubmit successful).