Re-land first pass BackgroundTracingManager.

content/browser/tracing/background_tracing_manager.h

Index: content/browser/tracing/background_tracing_manager.h
diff --git a/content/browser/tracing/background_tracing_manager.h b/content/browser/tracing/background_tracing_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..fb455a1e9e370dd15f6257fef06c0da9148d2a67
--- /dev/null
+++ b/content/browser/tracing/background_tracing_manager.h
@@ -0,0 +1,62 @@
+// 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_BROWSER_TRACING_BACKGROUND_TRACING_MANAGER_H_
+#define CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_MANAGER_H_
+
+#include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/trace_event/trace_event_impl.h"
+#include "content/browser/tracing/background_tracing_scenario.h"
+#include "content/common/content_export.h"
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+namespace content {
+class BrowserContext;
+class TraceUploader;
+};
+
+namespace net {
+class URLRequestContextGetter;
+};
+
+class BackgroundTracingEndpoint;
+
+class BackgroundTracingManager {
+ public:
+  BackgroundTracingManager();

[dsinclair, 2015/05/01 15:46:15]

If this is a singleton, should these not be private?

+  ~BackgroundTracingManager();
+
+  CONTENT_EXPORT static BackgroundTracingManager* GetInstance();
+
+  CONTENT_EXPORT void SetActiveScenario(
+      scoped_refptr<BackgroundTracingScenario>);
+
+  typedef base::Callback<void(bool)> StartedFinalizingCallback;
+
+  CONTENT_EXPORT void TryFinalizingBackgroundTracing(StartedFinalizingCallback);
+
+  bool is_gathering_for_testing() const { return is_gathering_; }
+  bool is_recording_for_testing() const { return is_recording_; }
+
+ private:
+  void EnableRecording();
+  void BeginFinalizingBackgroundTracing();
+  void OnFinalizeComplete();
+
+  scoped_refptr<BackgroundTracingScenario> active_scenario_;
+  bool is_gathering_;
+  bool is_recording_;

[dsinclair, 2015/05/01 15:46:14]

nit: Can these have a : 1?

+
+  base::WeakPtrFactory<BackgroundTracingManager> weak_ptr_factory_;
+
+  friend struct DefaultSingletonTraits<BackgroundTracingManager>;

[dsinclair, 2015/05/01 15:46:15]

nit: for some reason, I think these typlically come at the start of the private
section .... or I may just be making that up.

+
+  DISALLOW_COPY_AND_ASSIGN(BackgroundTracingManager);
+};
+
+#endif  // CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_MANAGER_H_