Change the base class of BlameContext into AsyncEnabledStateObserver

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 "base/json/json_writer.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/run_loop.h"
@@ skipping 55 matching lines @@
   buffer->AddFragment(json->data());
   if (!has_more_events)
     quit_closure.Run();
 }
 
 class BlameContextTest : public testing::Test {
  public:
   void StartTracing();
   void StopTracing();
   std::unique_ptr<trace_analyzer::TraceAnalyzer> CreateTraceAnalyzer();
+ protected:
+  MessageLoop loop_;
 };
 
 void BlameContextTest::StartTracing() {
   trace_event::TraceLog::GetInstance()->SetEnabled(
       trace_event::TraceConfig("*"), trace_event::TraceLog::RECORDING_MODE);
 }
 
 void BlameContextTest::StopTracing() {
   trace_event::TraceLog::GetInstance()->SetDisabled();
 }
@@ skipping 125 matching lines @@
       "}";
 
   std::string snapshot_json;
   JSONWriter::Write(*events[2]->GetKnownArgAsValue("snapshot"), &snapshot_json);
   EXPECT_EQ(kExpectedSnapshotJson, snapshot_json);
 }
 
 }  // namepace
 }  // namespace trace_event
 }  // namespace base