Remove use of deprecated MessageLoop methods in content.

content/browser/tracing/background_tracing_manager_impl.cc

 // Copyright 2015 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 "content/browser/tracing/background_tracing_manager_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/json/json_writer.h"
+#include "base/location.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "content/browser/tracing/background_tracing_rule.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/tracing_delegate.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
 
 namespace content {
 
@@ skipping 108 matching lines @@
   // we have to wait until initialization is finished to validate that the
   // scenario can run.
   if (BrowserThread::IsThreadInitialized(BrowserThread::IO)) {
     // TODO(oysteine): Retry when time_until_allowed has elapsed.
     if (config && delegate_ &&
         !delegate_->IsAllowedToBeginBackgroundScenario(
             *config.get(), requires_anonymized_data)) {
       return false;
     }
   } else {
-    base::MessageLoop::current()->PostTask(
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::Bind(&BackgroundTracingManagerImpl::ValidateStartupScenario,
                    base::Unretained(this)));
   }
 
   std::unique_ptr<const content::BackgroundTracingConfigImpl> config_impl(
       static_cast<BackgroundTracingConfigImpl*>(config.release()));
 
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
 
@@ skipping 395 matching lines @@
     case BackgroundTracingConfigImpl::CategoryPreset::BLINK_STYLE:
       return "blink_style";
     case BackgroundTracingConfigImpl::CategoryPreset::CATEGORY_PRESET_UNSET:
       NOTREACHED();
   }
   NOTREACHED();
   return "";
 }
 
 }  // namspace content