base: Remove the string logging from CHECK().

chromeos/network/onc/onc_test_utils.cc

Index: chromeos/network/onc/onc_test_utils.cc
diff --git a/chromeos/network/onc/onc_test_utils.cc b/chromeos/network/onc/onc_test_utils.cc
index d11f759c6727093704c22aad760cd04552c27b05..9fe09647adae0ceeb257dbf0dda0a76a9ef4ce02 100644
--- a/chromeos/network/onc/onc_test_utils.cc
+++ b/chromeos/network/onc/onc_test_utils.cc
@@ -57,13 +57,12 @@ std::unique_ptr<base::DictionaryValue> ReadTestDictionary(
   std::string error_message;
   std::unique_ptr<base::Value> content =
       deserializer.Deserialize(NULL, &error_message);
-  CHECK(content != NULL) << "Couldn't json-deserialize file '"
-                         << filename << "': " << error_message;
+  CHECK(content != NULL);
 
   dict = base::DictionaryValue::From(std::move(content));
-  CHECK(dict) << "File '" << filename
-              << "' does not contain a dictionary as expected, but type "
-              << content->GetType();
+  // File '|filename|' does not contain a dictionary as expected, but type
+  // |content->GetType()|
+  CHECK(dict);
   return dict;
 }