Add a feature flag for network service and about:flags entry for it.

content/child/runtime_features.cc

 // Copyright 2013 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 "content/child/runtime_features.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
@@ skipping 341 matching lines @@
                                                 false);
   if (base::FeatureList::IsEnabled(features::kCompositorTouchAction))
     WebRuntimeFeatures::EnableCompositorTouchAction(true);
 
   if (base::FeatureList::IsEnabled(features::kSkipCompositingSmallScrollers))
     WebRuntimeFeatures::EnableSkipCompositingSmallScrollers(true);
 
   if (base::FeatureList::IsEnabled(features::kGenericSensor))
     WebRuntimeFeatures::EnableGenericSensor(true);
 
-  if (base::FeatureList::IsEnabled(features::kLoadingWithMojo))
+  if (base::FeatureList::IsEnabled(features::kLoadingWithMojo) ||
+      base::FeatureList::IsEnabled(features::kNetworkService))
     WebRuntimeFeatures::EnableLoadingWithMojo(true);
 
   WebRuntimeFeatures::EnableMediaCastOverlayButton(
       base::FeatureList::IsEnabled(media::kMediaCastOverlayButton));
 
   if (!base::FeatureList::IsEnabled(features::kBlockCredentialedSubresources)) {
     WebRuntimeFeatures::EnableFeatureFromString("BlockCredentialedSubresources",
                                                 false);
   }
 
@@ skipping 30 matching lines @@
   if (command_line.HasSwitch(switches::kDisableBlinkFeatures)) {
     std::vector<std::string> disabled_features = base::SplitString(
         command_line.GetSwitchValueASCII(switches::kDisableBlinkFeatures),
         ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
     for (const std::string& feature : disabled_features)
       WebRuntimeFeatures::EnableFeatureFromString(feature, false);
   }
 }
 
 }  // namespace content