[update_engine] Update to use not-hideously-old logging API from chrome

BUG=None
TEST=compile

Change-Id: Ieed8952b6806a72b59e16c1579f7293b6a98157a

Review URL: http://codereview.chromium.org/3170010
diff --git a/mock_http_fetcher.cc b/mock_http_fetcher.cc
index abeff7a..04ec7f6 100644
--- a/mock_http_fetcher.cc
+++ b/mock_http_fetcher.cc
@@ -4,7 +4,7 @@
 
 #include "update_engine/mock_http_fetcher.h"
 #include <algorithm>
-#include "chromeos/obsolete_logging.h"
+#include "base/logging.h"
 
 // This is a mac implementation of HttpFetcher which is useful for testing.