Ensure that unit tests don't make network requests.

We already enforced this for browser tests.

Change-Id: I9481f3949f5ddfd71f54d6627243c4b4266d292c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636458Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665031}

content/public/test/unittest_test_suite.cc

@@ -12,6 +12,7 @@
 #include "base/test/test_suite.h"
 #include "build/build_config.h"
 #include "content/browser/network_service_instance_impl.h"
+#include "content/public/test/test_host_resolver.h"
 #include "content/test/test_blink_web_unit_test_support.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/blink/public/web/blink.h"
@@ -103,6 +104,7 @@ UnitTestTestSuite::UnitTestTestSuite(base::TestSuite* test_suite,
 #endif
   DCHECK(test_suite);
   blink_test_support_.reset(new TestBlinkWebUnitTestSupport);
+  test_host_resolver_ = std::make_unique<TestHostResolver>();
 }
 
 UnitTestTestSuite::~UnitTestTestSuite() = default;

content/public/test/unittest_test_suite.h

@@ -17,6 +17,7 @@ class TestSuite;
 
 namespace content {
 class TestBlinkWebUnitTestSupport;
+class TestHostResolver;
 
 // A special test suite that also initializes WebKit once for all unittests.
 // This is useful for two reasons:
@@ -39,6 +40,8 @@ class UnitTestTestSuite {
 
   std::unique_ptr<TestBlinkWebUnitTestSupport> blink_test_support_;
 
+  std::unique_ptr<TestHostResolver> test_host_resolver_;
+
   DISALLOW_COPY_AND_ASSIGN(UnitTestTestSuite);
 };