Update V8 to version 3.4.3.

R=sgjesse@chromium.org
BUG=None
TEST=existing tests.

Review URL: http://codereview.chromium.org/7044046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@88324 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -17,7 +17,7 @@ vars = {
   "libvpx_revision": "81610",
   "ffmpeg_revision": "83815",
   "skia_revision": "1537",
-  "v8_revision": "8211",
+  "v8_revision": "8218",
 }
 
 deps = {