Allow testing of Update 3 final

Upgrading to Update 3 is hitting a few roadblocks, which is preventing
Windows developers from getting its fast-incremental-linking goodness.
This change lets developers opt-in to using it by going:

    set DEPOT_TOOLS_WIN_TOOLCHAIN_PRERELEASE=1
    gclient runhooks

If the environment variable is not set then this has no effect.

BUG=627216

Review-Url: https://codereview.chromium.org/2263763002
Cr-Commit-Position: refs/heads/master@{#413279}


CrOS-Libchrome-Original-Commit: 0ea25a46ed83e529d928190cbf3259964acd3ad1
1 file changed
tree: ad9dc09f36d6a2ea4cb66f8d278a2461a4dbd8b6
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/