Introduce SystemNetworkContextManager.

content/network/network_service_unittest.cc

Index: content/network/network_service_unittest.cc
diff --git a/content/network/network_service_unittest.cc b/content/network/network_service_unittest.cc
index 29aa109e39c4a18eb5b0fee51fd0f9903f437aac..5a31c8ea2273c9a15d3f5fa65a75181c9e11ba4c 100644
--- a/content/network/network_service_unittest.cc
+++ b/content/network/network_service_unittest.cc
@@ -8,7 +8,7 @@
 #include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/network/network_context.h"
-#include "content/network/network_service.h"
+#include "content/network/network_service_impl.h"
 #include "content/public/common/network_service.mojom.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -21,7 +21,7 @@ class NetworkServiceTest : public testing::Test {
   NetworkServiceTest()
       : scoped_task_environment_(
             base::test::ScopedTaskEnvironment::MainThreadType::IO),
-        service_(NetworkService::CreateForTesting()) {}
+        service_(NetworkServiceImpl::CreateForTesting()) {}
   ~NetworkServiceTest() override {}
 
   NetworkService* service() const { return service_.get(); }