Proof of concept about BlameContext races on dtor.

base/trace_event/blame_context_unittest.cc

 // Copyright 2016 The Chromium 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 "base/trace_event/blame_context.h"
 
+#include <unistd.h>
+
 #include "base/json/json_writer.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/run_loop.h"
 #include "base/test/trace_event_analyzer.h"
 #include "base/trace_event/trace_buffer.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 namespace trace_event {
@@ skipping 187 matching lines @@
               "\"id_ref\":\"0x5678\","
               "\"scope\":\"TestBlameContextScope\""
           "}"
       "}";
 
   std::string snapshot_json;
   JSONWriter::Write(*events[2]->GetKnownArgAsValue("snapshot"), &snapshot_json);
   EXPECT_EQ(kExpectedSnapshotJson, snapshot_json);
 }
 
+class TestBlameContextWithSleep : public BlameContext {
+ public:
+  TestBlameContextWithSleep()
+      : BlameContext(kTestBlameContextCategory,
+                     kTestBlameContextName,
+                     kTestBlameContextType,
+                     kTestBlameContextScope,
+                     0,
+                     nullptr), destroyed_(false) {}
+
+ ~TestBlameContextWithSleep() override {
+    destroyed_ = true;
+    usleep(200000);  //anything longer than the PostDelayedTask below.
+ }
+
+ protected:
+  void AsValueInto(trace_event::TracedValue* state) override {
+    CHECK(!destroyed_) << "KABOOM, calling the derived AsValueInto after its "
+                          "dtor. Weird things will happen now.";
+  }
+
+  bool destroyed_;
+};
+
+TEST_F(BlameContextTest, DTOR) {
+  Thread thread("test thread");
+  thread.Start();
+  thread.task_runner()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&BlameContextTest::StartTracing, base::Unretained(this)),
+      TimeDelta::FromMicroseconds(100000));
+  std::unique_ptr<TestBlameContextWithSleep> derived(new TestBlameContextWithSleep());
+  derived->Initialize();
+  derived.reset();
+}
+
 }  // namepace
 }  // namespace trace_event
 }  // namespace base