Re-land first pass BackgroundTracingManager.

content/public/browser/background_tracing_upload_sink.h

+// 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.
+
+#ifndef CONTENT_PUBLIC_BROWSER_BACKGROUND_TRACING_UPLOAD_SINK_H_
+#define CONTENT_PUBLIC_BROWSER_BACKGROUND_TRACING_UPLOAD_SINK_H_
+
+#include "base/memory/ref_counted_memory.h"
+#include "base/trace_event/trace_event_impl.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Interface for trace data consumer. An implementation of this interface
+// is passed to SetActiveScenario() and receives the trace data.
+// This may happen on any thread.
+class BackgroundTracingUploadSink
+    : public base::RefCountedThreadSafe<BackgroundTracingUploadSink> {

[no sievers, 2015/05/19 19:52:22]

So this is for the embedder to implement?
Being RefCounted raises at least two questions:
- what thread will it be unref'd (and potentially be deleted) on?
- when will it be deleted?

It actually looks like with the current implementation, it might leak.

[shatch, 2015/05/20 18:23:16]

Spoke offline, liked your suggestion to just boil this down to a callback
instead of passing around this endpoint, so went with that.

+ public:
+  virtual void Upload(const std::string& contents,
+                      base::Callback<void()> done_callback) = 0;
+  virtual bool RequiresAnonymizedData() const = 0;
+
+ protected:
+  friend class base::RefCountedThreadSafe<BackgroundTracingUploadSink>;
+  virtual ~BackgroundTracingUploadSink() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_BACKGROUND_TRACING_UPLOAD_SINK_H_