[Mac] Enable AppNap for renderers

base/process/process_mac.cc

 // Copyright 2016 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.h"
 
 #include <mach/mach.h>
 
 #include "base/feature_list.h"
 #include "base/mac/mach_logging.h"
+#include "base/metrics/field_trial_params.h"
 
 namespace base {
 
+namespace {
+const char kAppNapFeatureParamName[] = "app_nap";
+}
+
 // Enables backgrounding hidden renderers on Mac.
 const Feature kMacAllowBackgroundingProcesses{"MacAllowBackgroundingProcesses",
                                               FEATURE_DISABLED_BY_DEFAULT};
 
+bool Process::IsAppNapEnabled() {
+  return !base::GetFieldTrialParamValueByFeature(
+              kMacAllowBackgroundingProcesses, kAppNapFeatureParamName)
+              .empty();
+}
+
 bool Process::CanBackgroundProcesses() {
-  return FeatureList::IsEnabled(kMacAllowBackgroundingProcesses);
+  return FeatureList::IsEnabled(kMacAllowBackgroundingProcesses) &&
+         !IsAppNapEnabled();
 }
 
 bool Process::IsProcessBackgrounded(PortProvider* port_provider) const {
   DCHECK(IsValid());
   if (port_provider == nullptr || !CanBackgroundProcesses())
     return false;
 
   mach_port_t task_port = port_provider->TaskForPid(Pid());
   if (task_port == TASK_NULL)
     return false;
@@ skipping 51 matching lines @@
                            TASK_QOS_POLICY_COUNT);
   if (result != KERN_SUCCESS) {
     MACH_LOG(ERROR, result) << "task_policy_set TASK_OVERRIDE_QOS_POLICY";
     return false;
   }
 
   return true;
 }
 
 }  // namespace base