update_engine: Update to build against libchrome-271506.

BUG=chromium:375032
TEST=`FEATURES=test emerge-$BOARD update_engine`

Change-Id: Ia7be302c12b439ad8aece51c9cbe128086626620
Reviewed-on: https://chromium-review.googlesource.com/201045
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/delta_performer_unittest.cc b/delta_performer_unittest.cc
index 21a6f8e..8051b32 100644
--- a/delta_performer_unittest.cc
+++ b/delta_performer_unittest.cc
@@ -321,10 +321,9 @@
 
     vector<char> zeros(16 * 1024, 0);
     EXPECT_EQ(zeros.size(),
-              file_util::WriteFile(
-                  base::FilePath(base::StringPrintf("%s/move-to-sparse",
-                                                    a_mnt.c_str())),
-                  zeros.data(), zeros.size()));
+              base::WriteFile(base::FilePath(base::StringPrintf(
+                                  "%s/move-to-sparse", a_mnt.c_str())),
+                              zeros.data(), zeros.size()));
 
     EXPECT_TRUE(
         WriteSparseFile(base::StringPrintf("%s/move-from-sparse",
@@ -382,10 +381,9 @@
 
     vector<char> zeros(16 * 1024, 0);
     EXPECT_EQ(zeros.size(),
-              file_util::WriteFile(
-                  base::FilePath(base::StringPrintf("%s/move-from-sparse",
-                                                    b_mnt.c_str())),
-                  zeros.data(), zeros.size()));
+              base::WriteFile(base::FilePath(base::StringPrintf(
+                                  "%s/move-from-sparse", b_mnt.c_str())),
+                              zeros.data(), zeros.size()));
 
     EXPECT_EQ(0, system(base::StringPrintf("dd if=/dev/zero "
                                            "of=%s/move-semi-sparse "