Cache the numberOfProcessors value on posix and expose it to blink

webkit/child/webkitplatformsupport_impl.cc

Index: webkit/child/webkitplatformsupport_impl.cc
diff --git a/webkit/child/webkitplatformsupport_impl.cc b/webkit/child/webkitplatformsupport_impl.cc
index 398b45c1c5c05d976be73cad1386f3ee9a0d98ff..d5bf20d63c4ad49c4f5e54e38301debe1b760be7 100644
--- a/webkit/child/webkitplatformsupport_impl.cc
+++ b/webkit/child/webkitplatformsupport_impl.cc
@@ -862,6 +862,10 @@ size_t WebKitPlatformSupportImpl::physicalMemoryMB() {
   return static_cast<size_t>(base::SysInfo::AmountOfPhysicalMemoryMB());
 }
 
+size_t WebKitPlatformSupportImpl::numberOfProcessors() {
+  return static_cast<size_t>(base::SysInfo::NumberOfProcessors());
+}
+
 void WebKitPlatformSupportImpl::startHeapProfiling(
   const blink::WebString& prefix) {
   // FIXME(morrita): Make this built on windows.