crash-reporter: Add diagnostics to help diagnose failures in the wild

system_logging.h

 // Copyright (c) 2010 The Chromium OS 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 CRASH_REPORTER_SYSTEM_LOGGING_H_
 #define CRASH_REPORTER_SYSTEM_LOGGING_H_
 
+#include <stdarg.h>
 #include <string>
 
 class SystemLogging {
  public:
   virtual void Initialize(const char *ident) = 0;
   virtual void LogInfo(const char *format, ...) = 0;
   virtual void LogWarning(const char *format, ...) = 0;
   virtual void LogError(const char *format, ...) = 0;
+  virtual void set_accumulator(std::string *accumulator) = 0;
 };
 
+// SystemLoggingImpl implements SystemLogging but adds the
+// capability of accumulating the log to a STL string.
 class SystemLoggingImpl : public SystemLogging {
  public:
   SystemLoggingImpl();
   virtual ~SystemLoggingImpl();
   virtual void Initialize(const char *ident);
   virtual void LogInfo(const char *format, ...);
   virtual void LogWarning(const char *format, ...);
   virtual void LogError(const char *format, ...);
+  virtual void set_accumulator(std::string *accumulator) {
+    accumulator_ = accumulator;
+  }
  private:
   static std::string identity_;
+  static std::string *accumulator_;
+  void LogWithLevel(int level, const char *format,
+                    va_list arg_list);
 };
 
 #endif  // CRASH_REPORTER_SYSTEM_LOGGING_H_