DNS: Support reprioritization of requests.

net/dns/host_resolver.cc

Index: net/dns/host_resolver.cc
diff --git a/net/dns/host_resolver.cc b/net/dns/host_resolver.cc
index abe8e49e6578714bf5216398b3450135b4798da1..f0a751e767df0f71dcd42acc1051effa72616b58 100644
--- a/net/dns/host_resolver.cc
+++ b/net/dns/host_resolver.cc
@@ -103,6 +103,11 @@ HostResolver::~HostResolver() {
 void HostResolver::SetDnsClientEnabled(bool enabled) {
 }
 
+void HostResolver::ChangeRequestPriority(RequestHandle req,
+                                         RequestPriority priority) {
+  NOTIMPLEMENTED();

[Randy Smith (Not in Mondays), 2016/04/28 18:04:40]

Why NOTIMPLEMENTED() rather than =0 in the declaration?

[Julia Tuttle, 2016/05/04 14:43:20]

Didn't want to update the dozen unittest mocks that are just going to
NOTIMPLEMENTED() or {} it themselves.

+}
+
 HostCache* HostResolver::GetHostCache() {
   return NULL;
 }