Fix clang compiler warning for lambda variable catpure

base/trace_event/memory_dump_manager_unittest.cc

Index: base/trace_event/memory_dump_manager_unittest.cc
diff --git a/base/trace_event/memory_dump_manager_unittest.cc b/base/trace_event/memory_dump_manager_unittest.cc
index 51d41943fba0416fd9ad5f167d78cbbbdbc51a1c..4e288ad37b8a5b52f971fbc5a4cec6560c53f518 100644
--- a/base/trace_event/memory_dump_manager_unittest.cc
+++ b/base/trace_event/memory_dump_manager_unittest.cc
@@ -774,8 +774,7 @@ TEST_F(MemoryDumpManagerTest, TestPollingOnDumpThread) {
   int call_count = 0;
   MemoryDumpManager* mdm = mdm_.get();
   const auto poll_function1 = [&call_count, &test_task_runner, quit_closure,
-                               &mdp2, mdm, &options, kPollsToQuit,
-                               this](uint64_t* total) -> void {
+                               &mdp2, mdm, &options](uint64_t* total) -> void {
     ++call_count;
     if (call_count == 1)
       RegisterDumpProvider(mdp2.get(), nullptr, options, kMDPName);