Adding shutdown tracing capabilities

content/browser/browser_shutdown_profile_dumper.h

+// Copyright (c) 2013 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_BROWSER_SHUTDOWN_PROFILE_DUMPER_H_
+#define CONTENT_BROWSER_BROWSER_SHUTDOWN_PROFILE_DUMPER_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_memory.h"
+#include "content/common/content_export.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace content {
+
+// This class is intended to dump the tracing results of the shutdown process
+// to a file before the browser process exits.
+// It will save the file either into the command line passed
+// "--trace-shutdown-file=<name>" parameter - or - to "chrometrace.log" in the
+// current directory.
+// Use the class with a scoped_ptr to get files written in the destructor.
+// Note that we cannot use the asynchronous file writer since the
+// |SequencedWorkerPool| will get killed in the shutdown process.
+class BrowserShutdownProfileDumper {
+ public:
+  BrowserShutdownProfileDumper();
+
+  ~BrowserShutdownProfileDumper();
+
+ private:
+  // Writes all traces which happened to disk.
+  void WriteTracesToDisc(const base::FilePath& file_name);
+
+  // Returns the file name where we should save the trace dump to.
+  base::FilePath GetFileName();
+
+  // The callback for the |TraceLog::Flush| function. It saves all traces to
+  // disc.
+  void WriteTraceDataCollected(
+      const scoped_refptr<base::RefCountedString>& events_str);
+
+  // Returns true if the dump file is valid.
+  bool IsFileValid();
+
+  // Writes a string to the dump file.
+  void WriteString(const std::string& string);
+
+  // Write a buffer to the dump file.
+  void WriteChars(const char* chars, size_t size);
+
+  // Closes the dump file.
+  void CloseFile();
+
+  // The number of blocks we have already written.
+  int blocks_;
+  // For dumping the content to disc.
+  FILE* dump_file_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserShutdownProfileDumper);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_BROWSER_SHUTDOWN_PROFILE_DUMPER_H_