Revert of Fix free memory calculation.

base/process/process_metrics.cc

 // Copyright 2013 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 "base/process/process_metrics.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/values.h"
 #include "build/build_config.h"
 
 namespace base {
 
-SystemMemoryInfoKB::SystemMemoryInfoKB() = default;
-
-SystemMemoryInfoKB::SystemMemoryInfoKB(const SystemMemoryInfoKB& other) =
-    default;
-
 SystemMetrics::SystemMetrics() {
   committed_memory_ = 0;
 }
 
 SystemMetrics SystemMetrics::Sample() {
   SystemMetrics system_metrics;
 
   system_metrics.committed_memory_ = GetSystemCommitCharge();
 #if defined(OS_LINUX) || defined(OS_ANDROID)
   GetSystemMemoryInfo(&system_metrics.memory_info_);
@@ skipping 65 matching lines @@
   return (wakeups_delta_for_ms + time_delta / 2) / time_delta;
 }
 #else
 int ProcessMetrics::GetIdleWakeupsPerSecond() {
   NOTIMPLEMENTED();  // http://crbug.com/120488
   return 0;
 }
 #endif  // defined(OS_MACOSX) || defined(OS_LINUX)
 
 }  // namespace base