[presubmit] Enabling readability/inheritance linter checking.

test/unittests/run-all-unittests.cc

 // Copyright 2014 the V8 project 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 "include/libplatform/libplatform.h"
 #include "include/v8.h"
 #include "src/base/compiler-specific.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace {
 
 class DefaultPlatformEnvironment final : public ::testing::Environment {
  public:
   DefaultPlatformEnvironment() : platform_(NULL) {}
-  ~DefaultPlatformEnvironment() {}
 
-  virtual void SetUp() override {
+  void SetUp() override {
     EXPECT_EQ(NULL, platform_);
     platform_ = v8::platform::CreateDefaultPlatform();
     ASSERT_TRUE(platform_ != NULL);
     v8::V8::InitializePlatform(platform_);
     ASSERT_TRUE(v8::V8::Initialize());
   }
 
-  virtual void TearDown() override {
+  void TearDown() override {
     ASSERT_TRUE(platform_ != NULL);
     v8::V8::Dispose();
     v8::V8::ShutdownPlatform();
     delete platform_;
     platform_ = NULL;
   }
 
  private:
   v8::Platform* platform_;
 };
 
 }  // namespace
 
 
 int main(int argc, char** argv) {
   testing::InitGoogleMock(&argc, argv);
   testing::AddGlobalTestEnvironment(new DefaultPlatformEnvironment);
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
   v8::V8::InitializeExternalStartupData(argv[0]);
   return RUN_ALL_TESTS();
 }