Telemetry / Devtools TraceHandler: exposes tracing via dev tools.

content/browser/debugger/devtools_trace_handler.h

Index: content/browser/debugger/devtools_trace_handler.h
diff --git a/content/browser/debugger/devtools_trace_handler.h b/content/browser/debugger/devtools_trace_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..61a33eba56bbbba4208cfb4d19624af836186428
--- /dev/null
+++ b/content/browser/debugger/devtools_trace_handler.h
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+// 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_BROWSER_DEBUGGER_DEVTOOLS_TRACE_HANDLER_H_
+#define CONTENT_BROWSER_DEBUGGER_DEVTOOLS_TRACE_HANDLER_H_
+
+#include "content/public/browser/trace_subscriber.h"
+
+namespace content {
+
+// This class bridges DevTools remote debugging server with the trace
+// infrastructure.
+class DevToolsTraceHandler : public TraceSubscriber {
+ public:
+  DevToolsTraceHandler();
+  ~DevToolsTraceHandler();
+
+  // TraceSubscriber:
+  virtual void OnEndTracingComplete();
+  virtual void OnTraceDataCollected(
+      const scoped_refptr<base::RefCountedString>& trace_fragment);
+
+  void BeginTracing(const std::string& categories);
+  void EndTracingAsync();
+  bool has_completed() const;
+
+  std::string GetAndResetTrace();
+
+ private:
+  bool has_completed_;
+
+  std::string buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DevToolsTraceHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_DEBUGGER_DEVTOOLS_TRACE_HANDLER_H_