[wasm] Stop the BranchTableIterator if there is an error in the decoder.

[wasm] Stop the BranchTableIterator if there is an error in the decoder.

In a fuzzer testcase I found locally the ast-decoder spent a lot of time
in the decoding of kExprBrTable after the decoder already found an
error. I did not add a test because the fuzzer test case did not
actually crash. It only run out of memory in the chromium fuzzer.

R=titzer@chromium.org

Committed: https://crrev.com/77bda187a50e2e1cbd26bae86a7cf511c34f0c1a
Cr-Commit-Position: refs/heads/master@{#40254}

[ahaas, 2016-10-13 11:26:30]

The CQ bit was checked by ahaas@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-13 11:26:40]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[titzer, 2016-10-13 11:30:48]

lgtm

[commit-bot: I haz the power, 2016-10-13 11:52:26]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-13 11:52:27]

Dry run: This issue passed the CQ dry run.

[ahaas, 2016-10-13 11:56:49]

The CQ bit was checked by ahaas@chromium.org

[commit-bot: I haz the power, 2016-10-13 11:56:56]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-13 11:58:56]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-13 11:59:13]

Description was changed from

==========
[wasm] Stop the BranchTableIterator if there is an error in the decoder.

In a fuzzer testcase I found locally the ast-decoder spent a lot of time
in the decoding of kExprBrTable after the decoder already found an
error. I did not add a test because the fuzzer test case did not
actually crash. It only run out of memory in the chromium fuzzer.

R=titzer@chromium.org
==========

to

==========
[wasm] Stop the BranchTableIterator if there is an error in the decoder.

In a fuzzer testcase I found locally the ast-decoder spent a lot of time
in the decoding of kExprBrTable after the decoder already found an
error. I did not add a test because the fuzzer test case did not
actually crash. It only run out of memory in the chromium fuzzer.

R=titzer@chromium.org

Committed: https://crrev.com/77bda187a50e2e1cbd26bae86a7cf511c34f0c1a
Cr-Commit-Position: refs/heads/master@{#40254}
==========

[commit-bot: I haz the power, 2016-10-13 11:59:14]

Patchset 1 (id:??) landed as
https://crrev.com/77bda187a50e2e1cbd26bae86a7cf511c34f0c1a
Cr-Commit-Position: refs/heads/master@{#40254}