[build] Pull "build" from chromium as dependency

DEPS

 # Note: The buildbots evaluate this file with CWD set to the parent
 # directory and assume that the root of the checkout is in ./v8/, so
 # all paths in here must match this assumption.
 
 vars = {
   "git_url": "https://chromium.googlesource.com",
 }
 
 deps = {
-  # TODO(machenbach): Add this. Need to be committed locally as trybots run
-  # gclient sync on a deps change before applying any other change.
-  # "v8/build":
-  #  Var("git_url") + "/chromium/src/build.git" + "@" + "7181610b0c84e2cd87852a7f7d30c4e7e4ca32cd",
+  "v8/build":
+    Var("git_url") + "/chromium/src/build.git" + "@" + "7181610b0c84e2cd87852a7f7d30c4e7e4ca32cd",
   "v8/tools/gyp":
     Var("git_url") + "/external/gyp.git" + "@" + "e24c83726b7294179f479a683eeb351568fcc4ee",
   "v8/third_party/icu":
     Var("git_url") + "/chromium/deps/icu.git" + "@" + "c291cde264469b20ca969ce8832088acb21e0c48",
   "v8/buildtools":
     Var("git_url") + "/chromium/buildtools.git" + "@" + "cdbd50759bf2289d2c9d3f1f7d02239b4b4b1209",
   "v8/base/trace_event/common":
     Var("git_url") + "/chromium/src/base/trace_event/common.git" + "@" + "c8c8665c2deaf1cc749d9f8e153256d4f67bf1b8",
   "v8/tools/swarming_client":
     Var('git_url') + '/external/swarming.client.git' + '@' + "df6e95e7669883c8fe9ef956c69a544154701a49",
@@ skipping 197 matching lines @@
     'name': 'clang',
     'pattern': '.',
     'action': ['python', 'v8/tools/clang/scripts/update.py', '--if-needed'],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", "v8/gypfiles/gyp_v8"],
   },
 ]