Revert "update_engine: Update libchrome APIS to r456626."

This reverts commit 663ff4b30b9f629a130ef6d357d462b897d4071e.

Reason for revert: Broke the mac_sdk
Exempt-From-Owner-Approval: Fixing mac_sdk

Change-Id: I8184ec58e74d62dca0deafb39340d4bd36bf40e0
diff --git a/common/subprocess_unittest.cc b/common/subprocess_unittest.cc
index 10710e8..cbc9a85 100644
--- a/common/subprocess_unittest.cc
+++ b/common/subprocess_unittest.cc
@@ -225,7 +225,7 @@
 TEST_F(SubprocessTest, CancelTest) {
   base::ScopedTempDir tempdir;
   ASSERT_TRUE(tempdir.CreateUniqueTempDir());
-  string fifo_path = tempdir.GetPath().Append("fifo").value();
+  string fifo_path = tempdir.path().Append("fifo").value();
   EXPECT_EQ(0, mkfifo(fifo_path.c_str(), 0666));
 
   // Start a process, make sure it is running and try to cancel it. We write