Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/225def8..99d7dc3

TBR=machenbach@chromium.org,vogelheim@chromium.org,hablich@chromium.org

Change-Id: If91d8fc6564ceb72f9bbe62be86d51d0913bf5df
Reviewed-on: https://chromium-review.googlesource.com/497952Reviewed-by: v8 autoroll <v8-autoroll@chromium.org>
Commit-Queue: v8 autoroll <v8-autoroll@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45149}

DEPS

@@ -8,7 +8,7 @@ vars = {
 
 deps = {
   "v8/build":
-    Var("chromium_url") + "/chromium/src/build.git" + "@" + "225def8ba5affc4d0d7f452077e89d6cc498b1c9",
+    Var("chromium_url") + "/chromium/src/build.git" + "@" + "99d7dc3269c37f8fca5270c76095e34c031f1939",
   "v8/tools/gyp":
     Var("chromium_url") + "/external/gyp.git" + "@" + "eb296f67da078ec01f5e3a9ea9cdc6d26d680161",
   "v8/third_party/icu":