Enable MSVC warning for unused locals.

chrome/browser/history/in_memory_url_index_unittest.cc

Index: chrome/browser/history/in_memory_url_index_unittest.cc
diff --git a/chrome/browser/history/in_memory_url_index_unittest.cc b/chrome/browser/history/in_memory_url_index_unittest.cc
index 2a79e0d58be101a547e56ce9738fe7ebf5cea401..6b436fb2b0e30719b7cba7dc2301e035aa775426 100644
--- a/chrome/browser/history/in_memory_url_index_unittest.cc
+++ b/chrome/browser/history/in_memory_url_index_unittest.cc
@@ -983,12 +983,11 @@ TEST_F(InMemoryURLIndexTest, WhitelistedURLs) {
     { "xmpp://guest@example.com", false },
   };
 
-  URLIndexPrivateData& private_data(*GetPrivateData());
   const std::set<std::string>& whitelist(scheme_whitelist());
   for (size_t i = 0; i < arraysize(data); ++i) {
     GURL url(data[i].url_spec);
     EXPECT_EQ(data[i].expected_is_whitelisted,
-              private_data.URLSchemeIsWhitelisted(url, whitelist));
+              GetPrivateData()->URLSchemeIsWhitelisted(url, whitelist));
   }
 }