Add dbghelp.dll that works on XP, and include in base.isolate

base/debug/stack_trace_win.cc

 // 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.
 
 #include "base/debug/stack_trace.h"
 
 #include <windows.h>
 #include <dbghelp.h>
 
 #include <iostream>
@@ skipping 134 matching lines @@
       // ERROR_INVALID_PARAMETER.
       // When it fails, we should not call debugbreak since it kills the current
       // process (prevents future tests from running or kills the browser
       // process).
       DLOG(ERROR) << "SymInitialize failed: " << init_error_;
       return;
     }
 
     init_error_ = ERROR_SUCCESS;
 
-    // Work around a mysterious hang on Windows XP.
-    if (base::win::GetVersion() < base::win::VERSION_VISTA)
-      return;
-
     // When transferring the binaries e.g. between bots, path put
     // into the executable will get off. To still retrieve symbols correctly,
     // add the directory of the executable to symbol search path.
     // All following errors are non-fatal.
     const size_t kSymbolsArraySize = 1024;
     scoped_ptr<wchar_t[]> symbols_path(new wchar_t[kSymbolsArraySize]);
 
     // Note: The below function takes buffer size as number of characters,
     // not number of bytes!
     if (!SymGetSearchPathW(GetCurrentProcess(),
@@ skipping 109 matching lines @@
       (*os) << "\t" << trace_[i] << "\n";
     }
   } else {
     (*os) << "Backtrace:\n";
     context->OutputTraceToStream(trace_, count_, os);
   }
 }
 
 }  // namespace debug
 }  // namespace base