NaCl: Update revision in DEPS, 8191c1a -> 66c300e

NaCl: Update revision in DEPS, 8191c1a -> 66c300e

This pulls in the following Native Client changes:

8c0ad9f: (brettw@chromium.org) Pull build directory into standalone native client checkouts.
ef7004b: (mseaborn@chromium.org) Cleanup: Merge the Unix/Windows implementations of NaClSysClock()
ab37312: (dschuff@chromium.org) Support nacl-clang in calingconv_case_by_case test
64bc071: (mseaborn@chromium.org) Cleanup: Use NACL_DEFINE/REGISTER_SYSCALL instead of NaClAddSyscall() in tests
3e51032: (dschuff@chromium.org) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
66c300e: (dschuff@chromium.org) Update revision for PNaCl

Changes: https://chromium.googlesource.com/native_client/src/native_client/+log/8191c1a953ca5896c715cb21e7a24d8c092f925f..66c300e071cf3e1c1fb98f9a3e15bb02b4388d72

BUG=none
TEST=browser_tests and nacl_integration
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_chromium_dbg_32_ng,linux_arm_compile,linux_nacl_sdk_build

Committed: https://crrev.com/4bc4972b29a29986614875f3efc526400c812cb1
Cr-Commit-Position: refs/heads/master@{#336038}

[Derek Schuff, 2015-06-24 20:54:42]

dschuff@chromium.org changed reviewers:
+ mseaborn@chromium.org

[Mark Seaborn, 2015-06-24 21:45:07]

Auto-LGTM

[Derek Schuff, 2015-06-24 22:38:27]

The CQ bit was checked by dschuff@chromium.org

[commit-bot: I haz the power, 2015-06-24 22:39:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1199253005/1

[commit-bot: I haz the power, 2015-06-24 23:01:09]

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

[commit-bot: I haz the power, 2015-06-24 23:01:10]

Exceeded global retry quota

[Derek Schuff, 2015-06-24 23:19:51]

The CQ bit was checked by dschuff@chromium.org

[commit-bot: I haz the power, 2015-06-24 23:21:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1199253005/1

[commit-bot: I haz the power, 2015-06-24 23:51:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-24 23:53:27]

Patchset 1 (id:??) landed as
https://crrev.com/4bc4972b29a29986614875f3efc526400c812cb1
Cr-Commit-Position: refs/heads/master@{#336038}