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.

Change-Id: I42e65bda7f1dbdf6f6e0ebf356d2cfea6b729193
diff --git a/common/test_utils.cc b/common/test_utils.cc
index f89c448..4d1e20d 100644
--- a/common/test_utils.cc
+++ b/common/test_utils.cc
@@ -142,7 +142,8 @@
   // Bind to an unused loopback device, sanity check the device name.
   lo_dev_name_p->clear();
   if (!(utils::ReadPipe("losetup --show -f " + filename, lo_dev_name_p) &&
-        base::StartsWithASCII(*lo_dev_name_p, "/dev/loop", true))) {
+        base::StartsWith(*lo_dev_name_p, "/dev/loop",
+                         base::CompareCase::SENSITIVE))) {
     ADD_FAILURE();
     return false;
   }