Update V8 DEPS.

Rolling v8/tools/mb to 3d628fb28050a1deef98e3be5d5b37b5fd8ed27f

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

Review-Url: https://codereview.chromium.org/2079213002
Cr-Commit-Position: refs/heads/master@{#37082}

DEPS

@@ -18,7 +18,7 @@ deps = {
   "v8/base/trace_event/common":
     Var("git_url") + "/chromium/src/base/trace_event/common.git" + "@" + "54b8455be9505c2cb0cf5c26bb86739c236471aa",
   "v8/tools/mb":
-    Var('git_url') + '/chromium/src/tools/mb.git' + '@' + "69858344b036b3694334ffe53829fe4cfad89822",
+    Var('git_url') + '/chromium/src/tools/mb.git' + '@' + "3d628fb28050a1deef98e3be5d5b37b5fd8ed27f",
   "v8/tools/swarming_client":
     Var('git_url') + '/external/swarming.client.git' + '@' + "df6e95e7669883c8fe9ef956c69a544154701a49",
   "v8/testing/gtest":