Update update engine to compile and use libchrome-180609.

Made the following fixes:
- base/eintr_wrapper.h -> base/posix/eintr_wrapper.h
- base/string_tokenizer.h -> base/strings/string_tokenizer.h
- Switched JSONReader->JsonToValue to use JSONReader->ReadToValue.

BUG=chromium-os:39847
TEST=unittests + run through image_to_live

Change-Id: Iffa0a3af4a065fac40460d8c1c2ed5c9b6e9ed07
Reviewed-on: https://gerrit.chromium.org/gerrit/44098
Reviewed-by: Chris Sosa <sosa@chromium.org>
Tested-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Chris Sosa <sosa@chromium.org>
diff --git a/omaha_hash_calculator.cc b/omaha_hash_calculator.cc
index 245706d..2159d28 100644
--- a/omaha_hash_calculator.cc
+++ b/omaha_hash_calculator.cc
@@ -6,8 +6,8 @@
 
 #include <fcntl.h>
 
-#include <base/eintr_wrapper.h>
 #include <base/logging.h>
+#include <base/posix/eintr_wrapper.h>
 #include <openssl/bio.h>
 #include <openssl/buffer.h>
 #include <openssl/evp.h>