AppendASCII returns a new object.

chrome/browser/safe_browsing/safe_browsing_database_unittest.cc

Index: chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc b/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
index 51c962dccafefd5565d4ca3f3fee9ff62a621f8a..5a94ea49788078be3599dfa9c8f6713d93b47fed 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
@@ -54,7 +54,7 @@ class SafeBrowsingDatabaseTest : public PlatformTest {
     file_deleter_.reset(new FileAutoDeleter(temp_dir));
 
     FilePath filename(temp_dir);
-    filename.AppendASCII("SafeBrowsingTestDatabase");
+    filename = filename.AppendASCII("SafeBrowsingTestDatabase");
 
     // In case it existed from a previous run.
     file_util::Delete(FilePath(filename.value() + kBloomSuffix), false);