Roll recipe dependencies (trivial).

This is an automated CL created by the recipe roller. This CL rolls recipe
changes from upstream projects (e.g. depot_tools) into downstream projects
(e.g. tools/build).

More info is at https://goo.gl/zkKdpD. Use https://goo.gl/noib3a to file a bug
(or complain)

build:
  https://crrev.com/1fb4c10e66e8a0c4c445e2a28a5bd66752a4634c Split dart2js test steps into observatory, co19, and others. (whesse@google.com)

TBR=martiniss@chromium.org,phajdan.jr@chromium.org
BUG=https://github.com/dart-lang/sdk/issues/27412

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Review-Url: https://codereview.chromium.org/2361853004
Cr-Commit-Position: refs/heads/master@{#420609}

infra/config/recipes.cfg

@@ -5,7 +5,7 @@ deps {
   project_id: "build"
   url: "https://chromium.googlesource.com/chromium/tools/build.git"
   branch: "master"
-  revision: "60ebc91bfe416e751ba02606db5292e244457d24"
+  revision: "1fb4c10e66e8a0c4c445e2a28a5bd66752a4634c"
 }
 deps {
   project_id: "depot_tools"