Deprecate NonThreadSafe in content/renderer/media in favor of SequenceChecker.

content/renderer/media/webrtc_uma_histograms.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_RENDERER_MEDIA_WEBRTC_UMA_HISTOGRAMS_H_
 #define CONTENT_RENDERER_MEDIA_WEBRTC_UMA_HISTOGRAMS_H_
 
 #include "base/macros.h"
 #include "base/memory/singleton.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "content/common/content_export.h"
 #include "content/public/common/media_stream_request.h"
 
 namespace content {
 
 // Used to investigate where UserMediaRequests end up.
 // Only UserMediaRequests that do not log with LogUserMediaRequestResult
 // should call LogUserMediaRequestWithNoResult.
 //
 // Elements in this enum should not be deleted or rearranged; the only
@@ skipping 38 matching lines @@
 
 // A singleton that keeps track of the number of MediaStreams being
 // sent over PeerConnections. It uses the transition to zero such
 // streams to demarcate the start of a new "session". Note that this
 // is a rough approximation of sessions, as you could conceivably have
 // multiple tabs using this renderer process, and each of them using
 // PeerConnections.
 //
 // The UpdateWebRTCMethodCount function above uses this class to log a
 // metric at most once per session.
-class CONTENT_EXPORT PerSessionWebRTCAPIMetrics : public base::NonThreadSafe {
+class CONTENT_EXPORT PerSessionWebRTCAPIMetrics {
  public:
   virtual ~PerSessionWebRTCAPIMetrics();
 
   static PerSessionWebRTCAPIMetrics* GetInstance();
 
   // Increment/decrement the number of streams being sent or received
   // over any current PeerConnection.
   void IncrementStreamCounter();
   void DecrementStreamCounter();
 
  protected:
   friend struct base::DefaultSingletonTraits<PerSessionWebRTCAPIMetrics>;
   friend void UpdateWebRTCMethodCount(JavaScriptAPIName);
 
   // Protected so that unit tests can test without this being a
   // singleton.
   PerSessionWebRTCAPIMetrics();
 
   // Overridable by unit tests.
   virtual void LogUsage(JavaScriptAPIName api_name);
 
   // Called by UpdateWebRTCMethodCount above. Protected rather than
   // private so that unit tests can call it.
   void LogUsageOnlyOnce(JavaScriptAPIName api_name);
 
  private:
   void ResetUsage();
 
   int num_streams_;
   bool has_used_api_[INVALID_NAME];

[mcasas, 2017/06/02 15:01:13]

<rant mode>
Ugh, this should be s/INVALID_NAME/NUM_APIS/ or some such.
</rant mode>

 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(PerSessionWebRTCAPIMetrics);
 };
 
 } //  namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBRTC_UMA_HISTOGRAMS_H_