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/gyp":
@@ skipping 12 matching lines @@
   "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",
   "v8/test/simdjs/data": Var("git_url") + "/external/github.com/tc39/ecmascript_simd.git" + "@" + "c8ef63c728283debc25891123eb00482fee4b8cd",
   "v8/test/test262/data":
     Var("git_url") + "/external/github.com/tc39/test262.git" + "@" + "fd44cd73dfbce0b515a2474b7cd505d6176a9eb5",
   "v8/tools/clang":
-    Var("git_url") + "/chromium/src/tools/clang.git" + "@" + "247bb6833987bc73051243230a1f3c949a9c9b92",
+    Var("git_url") + "/chromium/src/tools/clang.git" + "@" + "668876fb488c6e3c5860a367b7d9a7fb8821df76",
 }
 
 deps_os = {
   "android": {
     "v8/third_party/android_tools":
       Var("git_url") + "/android_tools.git" + "@" + "54492f99c84cab0826a8e656efeb33a1b1bf5a04",
   },
   "win": {
     "v8/third_party/cygwin":
       Var("git_url") + "/chromium/deps/cygwin.git" + "@" + "c89e446b273697fadf3a10ff1007a97c0b7de6df",
@@ skipping 123 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/build/gyp_v8"],
   },
 ]