Add StackTrace::ToString().

base/debug/stack_trace.h

 // Copyright (c) 2011 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 BASE_DEBUG_STACK_TRACE_H_
 #define BASE_DEBUG_STACK_TRACE_H_
 #pragma once
 
 #include <iosfwd>
+#include <string>
 
 #include "base/base_export.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 struct _EXCEPTION_POINTERS;
 #endif
 
 namespace base {
 namespace debug {
@@ skipping 25 matching lines @@
   // Gets an array of instruction pointer values. |*count| will be set to the
   // number of elements in the returned array.
   const void* const* Addresses(size_t* count) const;
 
   // Prints a backtrace to stderr
   void PrintBacktrace() const;
 
   // Resolves backtrace to symbols and write to stream.
   void OutputToStream(std::ostream* os) const;
 
+  // Resolves backtrace to symbols and returns as string.
+  std::string ToString() const;
+
  private:
   // From http://msdn.microsoft.com/en-us/library/bb204633.aspx,
   // the sum of FramesToSkip and FramesToCapture must be less than 63,
   // so set it to 62. Even if on POSIX it could be a larger value, it usually
   // doesn't give much more information.
   static const int kMaxTraces = 62;
 
   void* trace_[kMaxTraces];
   int count_;
 };
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_STACK_TRACE_H_