update_engine: Update libchrome APIs to r369476

The new libchrome has been ported from Chromium and some APIs have
changed. Make necessary changes at call sites.

(cherry picked from commit 0103c36caa2e38e034e0d22185736b9ccfb35c58)

Change-Id: I3dedd8b3f6e92ce8d3eeef99a76ad876c29db304
diff --git a/omaha_response.h b/omaha_response.h
index 3a5a889..60ec4ac 100644
--- a/omaha_response.h
+++ b/omaha_response.h
@@ -78,7 +78,7 @@
   // aka "Pacific Time".)
   int install_date_days = -1;
 };
-COMPILE_ASSERT(sizeof(off_t) == 8, off_t_not_64bit);
+static_assert(sizeof(off_t) == 8, "off_t not 64 bit");
 
 }  // namespace chromeos_update_engine