[android-webview] Skip signal handler registration on x86/64

[android-webview] Skip signal handler registration on x86/64

An intricate entangling of libsigchain, sigaction() chaining and
user-space SIGSEGV handling by binary translator cause persistent
crashes when a SIGSEGV handler is installed by a x86 library on
a hybrid application which uses both Arm and x86 libraries.
Backing out the crash handler as a temporary workaround.
More context in the related bug.

BUG=477444
Committed: https://crrev.com/c62077fbce7d6b2bdaa78b809498b740a3ae90f7
Cr-Commit-Position: refs/heads/master@{#325441}

[Primiano Tucci (use gerrit), 2015-04-15 21:44:25]

primiano@chromium.org changed reviewers:
+ torne@chromium.org

[Primiano Tucci (use gerrit), 2015-04-15 21:44:25]

Torne, this is part of a set of two cls (one for microdumps the other for the
crash version string).

crrev.com/1059543003 (version str)
crrev.com/1089303002 (microdumps)

[Primiano Tucci (use gerrit), 2015-04-15 21:44:26]

Torne, this is part of a set of two cls (one for microdumps the other for the
crash version string).

crrev.com/1059543003 (version str)
crrev.com/1089303002 (microdumps)

[Torne, 2015-04-16 13:44:42]

The CQ bit was checked by torne@chromium.org

[Torne, 2015-04-16 13:44:42]

lgtm

[commit-bot: I haz the power, 2015-04-16 13:45:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1059543003/20001

[commit-bot: I haz the power, 2015-04-16 14:21:05]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-16 14:21:51]

Patchset 2 (id:??) landed as
https://crrev.com/c62077fbce7d6b2bdaa78b809498b740a3ae90f7
Cr-Commit-Position: refs/heads/master@{#325441}