Telemetry / Devtools TraceHandler: exposes tracing via dev tools.

content/browser/debugger/devtools_tracing_handler.h

Index: content/browser/debugger/devtools_tracing_handler.h
diff --git a/content/browser/debugger/devtools_tracing_handler.h b/content/browser/debugger/devtools_tracing_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..a5858fc3aa61eb1eb5f1d1374a116b8f29fdbdba
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+++ b/content/browser/debugger/devtools_tracing_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_TRACING_HANDLER_H_
+#define CONTENT_BROWSER_DEBUGGER_DEVTOOLS_TRACING_HANDLER_H_
+
+#include "content/browser/debugger/devtools_browser_target.h"
+#include "content/public/browser/trace_subscriber.h"
+
+namespace content {
+
+// This class bridges DevTools remote debugging server with the trace
+// infrastructure.
+class DevToolsTracingHandler
+    : public TraceSubscriber,
+      public DevToolsBrowserTarget::Handler {
+ public:
+  DevToolsTracingHandler();
+  virtual ~DevToolsTracingHandler();
+
+  // TraceSubscriber:
+  virtual void OnEndTracingComplete() OVERRIDE;;
+  virtual void OnTraceDataCollected(
+      const scoped_refptr<base::RefCountedString>& trace_fragment) OVERRIDE;
+
+  // DevToolBrowserTarget::Handler:
+  virtual std::string Domain() OVERRIDE;
+  virtual base::Value* OnProtocolCommand(
+      const std::string& method,
+      const base::DictionaryValue* params,
+      base::Value** error_out) OVERRIDE;
+
+ private:
+  base::Value* Start(const base::DictionaryValue* params);
+  base::Value* End(const base::DictionaryValue* params);
+  base::Value* HasCompleted(const base::DictionaryValue* params);
+  base::Value* GetTraceAndReset(const base::DictionaryValue* params);
+
+  bool has_completed_;
+
+  std::vector<std::string> buffer_;
+  int buffer_data_size_;
+
+  DISALLOW_COPY_AND_ASSIGN(DevToolsTracingHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_DEBUGGER_DEVTOOLS_TRACING_HANDLER_H_