base: Remove the string logging from CHECK().

net/proxy/proxy_config_service_linux_unittest.cc

Index: net/proxy/proxy_config_service_linux_unittest.cc
diff --git a/net/proxy/proxy_config_service_linux_unittest.cc b/net/proxy/proxy_config_service_linux_unittest.cc
index ae17d54321461b4c726f2295acf68777a99b0e96..cc2761cf15db690f1dbe2e8e0e89a4fdabcb4222 100644
--- a/net/proxy/proxy_config_service_linux_unittest.cc
+++ b/net/proxy/proxy_config_service_linux_unittest.cc
@@ -92,7 +92,8 @@ struct SettingsTable {
   value_type Get(key_type key) {
     auto it = settings.find(key);
     // In case there's a typo or the unittest becomes out of sync.
-    CHECK(it != settings.end()) << "key " << key << " not found";
+    // key |key| not found
+    CHECK(it != settings.end());
     value_type* value_ptr = it->second;
     return *value_ptr;
   }