[cleanup] Mark libplatform methods in subclasses with override.

Fixing clang-tidy warning.

Bug: v8:8015
Change-Id: I85fc4ba0e4188d60d15e389e4682541c65324b55
Reviewed-on: https://chromium-review.googlesource.com/1227071
Commit-Queue: Florian Sattler <sattlerf@google.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55920}

src/libplatform/default-platform.h

@@ -35,7 +35,7 @@ class V8_PLATFORM_EXPORT DefaultPlatform : public NON_EXPORTED_BASE(Platform) {
       IdleTaskSupport idle_task_support = IdleTaskSupport::kDisabled,
       std::unique_ptr<v8::TracingController> tracing_controller = {});
 
-  virtual ~DefaultPlatform();
+  ~DefaultPlatform() override;
 
   void SetThreadPoolSize(int thread_pool_size);
 

src/libplatform/default-worker-threads-task-runner.h

@@ -19,7 +19,7 @@ class V8_PLATFORM_EXPORT DefaultWorkerThreadsTaskRunner
  public:
   DefaultWorkerThreadsTaskRunner(uint32_t thread_pool_size);
 
-  ~DefaultWorkerThreadsTaskRunner();
+  ~DefaultWorkerThreadsTaskRunner() override;
 
   void Terminate();
 

src/libplatform/tracing/trace-buffer.h

@@ -18,7 +18,7 @@ namespace tracing {
 class TraceBufferRingBuffer : public TraceBuffer {
  public:
   TraceBufferRingBuffer(size_t max_chunks, TraceWriter* trace_writer);
-  ~TraceBufferRingBuffer();
+  ~TraceBufferRingBuffer() override;
 
   TraceObject* AddTraceEvent(uint64_t* handle) override;
   TraceObject* GetEventByHandle(uint64_t handle) override;

src/libplatform/tracing/trace-writer.h

@@ -15,7 +15,7 @@ class JSONTraceWriter : public TraceWriter {
  public:
   explicit JSONTraceWriter(std::ostream& stream);
   JSONTraceWriter(std::ostream& stream, const std::string& tag);
-  ~JSONTraceWriter();
+  ~JSONTraceWriter() override;
   void AppendTraceEvent(TraceObject* trace_event) override;
   void Flush() override;
 

src/libplatform/worker-thread.h

@@ -21,7 +21,7 @@ class TaskQueue;
 class V8_PLATFORM_EXPORT WorkerThread : public NON_EXPORTED_BASE(base::Thread) {
  public:
   explicit WorkerThread(TaskQueue* queue);
-  virtual ~WorkerThread();
+  ~WorkerThread() override;
 
   // Thread implementation.
   void Run() override;

test/unittests/libplatform/default-platform-unittest.cc

@@ -17,13 +17,15 @@ namespace default_platform_unittest {
 namespace {
 
 struct MockTask : public Task {
-  virtual ~MockTask() { Die(); }
+  // See issue v8:8185
+  ~MockTask() /* override */ { Die(); }
   MOCK_METHOD0(Run, void());
   MOCK_METHOD0(Die, void());
 };
 
 struct MockIdleTask : public IdleTask {
-  virtual ~MockIdleTask() { Die(); }
+  // See issue v8:8185
+  ~MockIdleTask() /* override */ { Die(); }
   MOCK_METHOD1(Run, void(double deadline_in_seconds));
   MOCK_METHOD0(Die, void());
 };
@@ -242,10 +244,10 @@ class TestBackgroundTask : public Task {
   explicit TestBackgroundTask(base::Semaphore* sem, bool* executed)
       : sem_(sem), executed_(executed) {}
 
-  virtual ~TestBackgroundTask() { Die(); }
+  ~TestBackgroundTask() override { Die(); }
   MOCK_METHOD0(Die, void());
 
-  void Run() {
+  void Run() override {
     *executed_ = true;
     sem_->Signal();
   }

test/unittests/libplatform/worker-thread-unittest.cc

@@ -17,7 +17,8 @@ namespace platform {
 namespace {
 
 struct MockTask : public Task {
-  virtual ~MockTask() { Die(); }
+  // See issue v8:8185
+  ~MockTask() /* override */ { Die(); }
   MOCK_METHOD0(Run, void());
   MOCK_METHOD0(Die, void());
 };