Update PartitionConnectionsByNetworkIsolationKey field trial config.

Add splitting the DNS cache experiment, prior to updating the
server-side field trial to include that feature.

Also fix NetInternalsTest test fixture to be compatible with splitting
the DNS cache by NetworkIsolationKey.

Bug: 963480
Change-Id: Iba98d8e27a9692ab2fe2bcbbe73a15bfd3415bd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2150685Reviewed-by: Eric Orth <ericorth@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760247}

chrome/browser/ui/webui/net_internals/net_internals_ui_browsertest.cc

@@ -147,6 +147,11 @@ class NetInternalsTest::MessageHandler : public content::WebUIMessageHandler {
 
   NetInternalsTest* net_internals_test_;
 
+  // Single NetworkIsolationKey used for all DNS lookups, so repeated lookups
+  // use the same cache key.
+  net::NetworkIsolationKey network_isolation_key_{
+      net::NetworkIsolationKey::CreateTransient()};
+
   base::WeakPtrFactory<MessageHandler> weak_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(MessageHandler);
@@ -230,8 +235,7 @@ void NetInternalsTest::MessageHandler::DnsLookup(
                                      weak_factory_.GetWeakPtr()));
   content::BrowserContext::GetDefaultStoragePartition(browser()->profile())
       ->GetNetworkContext()
-      ->ResolveHost(net::HostPortPair(hostname, 80),
-                    net::NetworkIsolationKey::CreateTransient(),
+      ->ResolveHost(net::HostPortPair(hostname, 80), network_isolation_key_,
                     std::move(resolve_host_parameters), std::move(client));
 }
 

testing/variations/fieldtrial_testing_config.json

@@ -3986,11 +3986,12 @@
             ],
             "experiments": [
                 {
-                    "name": "PartitionConnectionsAndSSLSessionsAndQuic",
+                    "name": "Enabled4",
                     "enable_features": [
                         "PartitionConnectionsByNetworkIsolationKey",
                         "PartitionHttpServerPropertiesByNetworkIsolationKey",
-                        "PartitionSSLSessionsByNetworkIsolationKey"
+                        "PartitionSSLSessionsByNetworkIsolationKey",
+                        "SplitHostCacheByNetworkIsolationKey"
                     ]
                 }
             ]