Update libchromiumcontent

Backport https://codereview.chromium.org/1324513002.

script/lib/config.py

@@ -8,7 +8,7 @@ import sys
 
 BASE_URL = os.getenv('LIBCHROMIUMCONTENT_MIRROR') or \
     'http://gh-contractor-zcbenz.s3.amazonaws.com/libchromiumcontent'
-LIBCHROMIUMCONTENT_COMMIT = '464aff2398f619b1d4d91b9187de69803919dca2'
+LIBCHROMIUMCONTENT_COMMIT = '17a4337f7948a45b5ea4b8f391df152ba8db5979'
 
 PLATFORM = {
   'cygwin': 'win32',