Refactor AppendToFile and WriteFileDescriptor

components/metrics/serialization/serialization_utils.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/metrics/serialization/serialization_utils.h"
 
 #include <sys/file.h>
 
 #include <string>
 #include <vector>
@@ skipping 178 matching lines @@
 
   std::string msg = sample.ToString();
   int32 size = msg.length() + sizeof(int32);
   if (size > kMessageMaxLength) {
     DLOG(ERROR) << "cannot write message: too long";
     return false;
   }
 
   // The file containing the metrics samples will only be read by programs on
   // the same device so we do not check endianness.
-  if (base::WriteFileDescriptor(file_descriptor.get(),
-                                reinterpret_cast<char*>(&size),
-                                sizeof(size)) != sizeof(size)) {
-    DLOG(ERROR) << "error writing message length " << errno;
+  if (!base::WriteFileDescriptor(file_descriptor.get(),
+                                 reinterpret_cast<char*>(&size),
+                                 sizeof(size))) {
+    DPLOG(ERROR) << "error writing message length";
     return false;
   }
 
-  if (base::WriteFileDescriptor(
-          file_descriptor.get(), msg.c_str(), msg.length()) !=
-      static_cast<int>(msg.length())) {
-    DLOG(ERROR) << "error writing message" << errno;
+  if (!base::WriteFileDescriptor(
+          file_descriptor.get(), msg.c_str(), msg.size())) {
+    DPLOG(ERROR) << "error writing message";
     return false;
   }
 
   return true;
 }
 
 }  // namespace metrics