[Mac] Enable AppNap for renderers

base/process/process.h

Index: base/process/process.h
diff --git a/base/process/process.h b/base/process/process.h
index 8979dd4ab56d1c13992d24dbf0ed29feea479744..9902fafdca5194fe41ca90a3b6581ed27fe7383d 100644
--- a/base/process/process.h
+++ b/base/process/process.h
@@ -139,6 +139,9 @@ class BASE_EXPORT Process {
   // Returns true if the priority was changed, false otherwise. If
   // |port_provider| is null, this is a no-op and it returns false.
   bool SetProcessBackgrounded(PortProvider* port_provider, bool value);
+
+  // Returns |true| if helper processes should participate in AppNap.
+  static bool IsAppNapEnabled();
 #else
   // A process is backgrounded when it's priority is lower than normal.
   // Return true if this process is backgrounded, false otherwise.