diff --git a/libweave/external/base/strings/stringprintf.h b/libweave/external/base/strings/stringprintf.h
new file mode 100644
index 0000000..523f7ee
--- /dev/null
+++ b/libweave/external/base/strings/stringprintf.h
@@ -0,0 +1,59 @@
+// Copyright 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 BASE_STRINGS_STRINGPRINTF_H_
+#define BASE_STRINGS_STRINGPRINTF_H_
+
+#include <stdarg.h>   // va_list
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+
+namespace base {
+
+// Return a C++ string given printf-like input.
+BASE_EXPORT std::string StringPrintf(const char* format, ...)
+    PRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
+#if defined(OS_WIN)
+BASE_EXPORT std::wstring StringPrintf(const wchar_t* format, ...)
+    WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
+#endif
+
+// Return a C++ string given vprintf-like input.
+BASE_EXPORT std::string StringPrintV(const char* format, va_list ap)
+    PRINTF_FORMAT(1, 0) WARN_UNUSED_RESULT;
+
+// Store result into a supplied string and return it.
+BASE_EXPORT const std::string& SStringPrintf(std::string* dst,
+                                             const char* format, ...)
+    PRINTF_FORMAT(2, 3);
+#if defined(OS_WIN)
+BASE_EXPORT const std::wstring& SStringPrintf(std::wstring* dst,
+                                              const wchar_t* format, ...)
+    WPRINTF_FORMAT(2, 3);
+#endif
+
+// Append result to a supplied string.
+BASE_EXPORT void StringAppendF(std::string* dst, const char* format, ...)
+    PRINTF_FORMAT(2, 3);
+#if defined(OS_WIN)
+BASE_EXPORT void StringAppendF(std::wstring* dst, const wchar_t* format, ...)
+    WPRINTF_FORMAT(2, 3);
+#endif
+
+// Lower-level routine that takes a va_list and appends to a specified
+// string.  All other routines are just convenience wrappers around it.
+BASE_EXPORT void StringAppendV(std::string* dst, const char* format, va_list ap)
+    PRINTF_FORMAT(2, 0);
+#if defined(OS_WIN)
+BASE_EXPORT void StringAppendV(std::wstring* dst,
+                               const wchar_t* format, va_list ap)
+    WPRINTF_FORMAT(2, 0);
+#endif
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRINGPRINTF_H_