Update V8 DEPS.

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 = {
   "v8/build":
-    Var("git_url") + "/chromium/src/build.git" + "@" + "7580e8854eb309008f00f115ea0adb13dac454a4",
+    Var("git_url") + "/chromium/src/build.git" + "@" + "f56976d676dfd5597229b21a83a53a58704582bf",
   "v8/tools/gyp":
     Var("git_url") + "/external/gyp.git" + "@" + "35eafcd939515d51d19556c543f9cf97faf75ee6",
   "v8/third_party/icu":
     Var("git_url") + "/chromium/deps/icu.git" + "@" + "ffa4b6704cf5cc9fec9485731f24a05b2ba94bca",
   "v8/buildtools":
-    Var("git_url") + "/chromium/buildtools.git" + "@" + "4dcb5ed1079e7a527061925637b8cc627e289e82",
+    Var("git_url") + "/chromium/buildtools.git" + "@" + "56eaae134648135663c4aa1ed82278572b5f35ef",
   "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' + '@' + "8b4a59c463a697a3e418c28e85f534e87337ba7f",
+    Var('git_url') + '/chromium/src/tools/mb.git' + '@' + "5268873c8c1eebbf1a3aaed7e63f99b600fab65e",
   "v8/tools/swarming_client":
     Var('git_url') + '/external/swarming.client.git' + '@' + "df6e95e7669883c8fe9ef956c69a544154701a49",
   "v8/testing/gtest":
     Var("git_url") + "/external/github.com/google/googletest.git" + "@" + "6f8a66431cb592dad629028a50b3dd418a408c87",
   "v8/testing/gmock":
     Var("git_url") + "/external/googlemock.git" + "@" + "0421b6f358139f02e102c9c332ce19a33faf75be",
   "v8/test/benchmarks/data":
     Var("git_url") + "/v8/deps/third_party/benchmarks.git" + "@" + "05d7188267b4560491ff9155c5ee13e207ecd65f",
   "v8/test/mozilla/data":
     Var("git_url") + "/v8/deps/third_party/mozilla-tests.git" + "@" + "f6c578a10ea707b1a8ab0b88943fe5115ce2b9be",
@@ skipping 203 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"],
   },
 ]