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":
     Var("git_url") + "/external/gyp.git" + "@" + "4d7c139b1820c5fcb993868c61f170a02cda8a40",
   "v8/third_party/icu":
     Var("git_url") + "/chromium/deps/icu.git" + "@" + "4e3266f32c62d30a3f9e2232a753c60129d1e670",
   "v8/buildtools":
     Var("git_url") + "/chromium/buildtools.git" + "@" + "da0df3fdac6036e862addb1155a2d6c11b6c18d5",
   "v8/testing/gtest":
     Var("git_url") + "/external/googletest.git" + "@" + "be1868139ffe0ccd0e8e3b37292b84c821d9c8ad",
   "v8/testing/gmock":
     Var("git_url") + "/external/googlemock.git" + "@" + "29763965ab52f24565299976b936d1265cb6a271",  # from svn revision 501
   "v8/tools/clang":
-    Var("git_url") + "/chromium/src/tools/clang.git" + "@" + "5489bbf01a5292a6c44d4cad7875ba2cb4ac975b",
+    Var("git_url") + "/chromium/src/tools/clang.git" + "@" + "4b5142322face2df2374a246dba98ae82be317b0",
 }
 
 deps_os = {
   "android": {
     "v8/third_party/android_tools":
       Var("git_url") + "/android_tools.git" + "@" + "4f723e2a5fa5b7b8a198072ac19b92344be2b271",
   },
   "win": {
     "v8/third_party/cygwin":
       Var("git_url") + "/chromium/deps/cygwin.git" + "@" + "c89e446b273697fadf3a10ff1007a97c0b7de6df",
@@ skipping 54 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"],
   },
 ]