Remove unused NetworkChangeManager interface handler.

GetNetworkChangeManager was incorrectly added in r577168 but was
never called. This change removes that vestigial code.

Bug: 836188
Change-Id: I618712829d04e94c1bb4e2c1d3fe5c16475daa6f
Reviewed-on: https://chromium-review.googlesource.com/c/1271556Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Chris Mumford <cmumford@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603261}

content/browser/renderer_host/render_process_host_impl.cc

@@ -1228,12 +1228,6 @@ void CopyFeatureSwitch(const base::CommandLine& src,
     dest->AppendSwitchASCII(switch_name, base::JoinString(features, ","));
 }
 
-void GetNetworkChangeManager(
-    network::mojom::NetworkChangeManagerRequest request) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  GetNetworkService()->GetNetworkChangeManager(std::move(request));
-}
-
 std::set<int>& GetCurrentCorbPluginExceptions() {
   static base::NoDestructor<std::set<int>> s_data;
   return *s_data;
@@ -2290,9 +2284,6 @@ void RenderProcessHostImpl::RegisterMojoInterfaces() {
   registry->AddInterface(base::BindRepeating(&KeySystemSupportImpl::Create));
 #endif  // BUILDFLAG(ENABLE_LIBRARY_CDMS)
 
-  AddUIThreadInterface(registry.get(),
-                       base::BindRepeating(&GetNetworkChangeManager));
-
   AddUIThreadInterface(
       registry.get(),
       base::BindRepeating(&RenderProcessHostImpl::BindVideoDecoderService,