Ok, I think the problem is in cros_setup_toolchains.py.  When it replaces use_ccache, it uses the old indentation rather than the new indentation.  I will create a CL and test to see if I can 1). reproduce the problem and 2). fix it with the CL.

The CL that I *think* fixes the problem is https://chromium-review.googlesource.com/c/522747/.  I'm still testing it.

The fix has been committed (it was chumped).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/ce9e9232d0662ee7dda70df241bde772cdfb4c8e

commit ce9e9232d0662ee7dda70df241bde772cdfb4c8e
Author: Caroline Tice <cmtice@google.com>
Date: Fri Jun 02 18:35:17 2017

Fix indentation problem for toolchain wrapper scripts.

The indentation of the code in the toolchain wrapper scripts was
changed in CL:489563, but the code int cros_setup_toolchains was
not changed to respect the new indentation.  This causes issues with
the Chrome Simple Workflow.  This CL fixes that problem.

BUG= chromium:729016 
TEST=In Progress

Change-Id: I7ff956db47dd6b86e834f13c5c720d655f29b266
Reviewed-on: https://chromium-review.googlesource.com/522747
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Caroline Tice <cmtice@chromium.org>
Tested-by: Caroline Tice <cmtice@chromium.org>
Trybot-Ready: Caroline Tice <cmtice@chromium.org>

[modify] https://crrev.com/ce9e9232d0662ee7dda70df241bde772cdfb4c8e/scripts/cros_setup_toolchains.py

.the CL that has been chumped will fix the problem, but users (and others) won't see the fix until it has gone through the chromiumos-sdk.   The bug they are seeing is in a bad toolchain that they are downloading from gs://chromiumos-sdk/2017/05/*-2017.05.31.232412.tar.xz .   I stopped the chromiumos-sdk build (which started around 5am this morning) , so the new builder has restarted with my patch, but it won't push a good toolchain package for about 16 hours.  In the meantime, the ideal solution would be to delete the 'bad' sdk toolchains that got pushed to gs, but I don't have the privileges to do that and I'm not sure if that would have other bad repercussions.

The bad packages are:
gs://chromiumos-sdk/2017/05/aarch64-cros-linux-gnu-2017.05.31.232412.tar.xz
gs://chromiumos-sdk/2017/05/arm-none-eabi-2017.05.31.232412.tar.xz
gs://chromiumos-sdk/2017/05/armv6j-cros-linux-gnueabi-2017.05.31.232412.tar.xz
gs://chromiumos-sdk/2017/05/armv7a-cros-linux-gnueabi-2017.05.31.232412.tar.xz
gs://chromiumos-sdk/2017/05/i686-pc-linux-gnu-2017.05.31.232412.tar.xz
gs://chromiumos-sdk/2017/05/mipsel-cros-linux-gnu-2017.05.31.232412.tar.xz
gs://chromiumos-sdk/2017/05/x86_64-cros-linux-gnu-2017.05.31.232412.tar.xz

you should never mess with artifacts in GS once they're uploaded.  please never try to do that without first consulting with the build team.

that's not how versions are discovered anyways ... they're picked up via chromiumos-overlay/chromeos/binhost/host/sdk_version.conf which you can modify/revert.

https://chromium-review.googlesource.com/522944

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/c260a711f37cef043b37bbc2f3dffcb6135b103a

commit c260a711f37cef043b37bbc2f3dffcb6135b103a
Author: Caroline Tice <cmtice@google.com>
Date: Fri Jun 02 20:36:16 2017

Use old sdk_version to revert bad wrapper change.

This reverts the sdk_version to the last good version
(until the latest chromiumos-sdk, with bug fix, completes).

Bug= chromium:729016 
TEST=Downloaded this version of sdk & verified it did not contain
the problem.

Change-Id: Ica0443934c6f7e298f9f2a143a7d63ec8d4a9531
Reviewed-on: https://chromium-review.googlesource.com/522944
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Commit-Queue: Caroline Tice <cmtice@chromium.org>
Tested-by: Caroline Tice <cmtice@chromium.org>
Trybot-Ready: Caroline Tice <cmtice@chromium.org>

[modify] https://crrev.com/c260a711f37cef043b37bbc2f3dffcb6135b103a/chromeos/binhost/host/sdk_version.conf

Closing. Please reopen it if its not fixed. Thanks!