Update v8 to version 2.5.4.

DEPS

 vars = {
   # Use this googlecode_url variable only if there is an internal mirror for it.
   # If you do not know, use the full path while defining your new deps entry.
   "googlecode_url": "http://%s.googlecode.com/svn",
   "webkit_trunk": "http://svn.webkit.org/repository/webkit/trunk",
   "nacl_trunk": "http://src.chromium.org/native_client/trunk",
   "webkit_revision": "71175",
   "skia_revision": "621",
   "chromium_git": "http://git.chromium.org/git",
   "swig_revision": "40423",
@@ skipping 40 matching lines @@
   "src/third_party/safe_browsing/testing":
     (Var("googlecode_url") % "google-safe-browsing") + "/trunk/testing@102",
 
   "src/third_party/cacheinvalidation/files":
     (Var("googlecode_url") % "google-cache-invalidation-api") + "/trunk@51",
 
   "src/tools/gyp":
     (Var("googlecode_url") % "gyp") + "/trunk@851",
 
   "src/v8":
-    (Var("googlecode_url") % "v8") + "/trunk@5748",
+    (Var("googlecode_url") % "v8") + "/trunk@5757",
 
   "src/native_client":
     Var("nacl_trunk") + "/src/native_client@" + Var("nacl_revision"),
   "src/chrome/test/data/extensions/api_test/permissions/nacl_enabled/bin":
     Var("nacl_trunk") + "/src/native_client/tests/prebuilt@" +
     Var("nacl_revision"),
 
   "src/third_party/skia/src":
     (Var("googlecode_url") % "skia") + "/trunk/src@" + Var("skia_revision"),
 
@@ skipping 237 matching lines @@
 ]
 
 
 hooks = [
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", "src/build/gyp_chromium"],
   },
 ]