Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

26 files changed, 7090 insertions, 0 deletions

diff --git a/security/sandbox/chromium/base/strings/char_traits.h b/security/sandbox/chromium/base/strings/char_traits.h
new file mode 100644
index 0000000000..b193e216cc
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/char_traits.h
@@ -0,0 +1,92 @@
+// Copyright 2018 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_CHAR_TRAITS_H_
+#define BASE_STRINGS_CHAR_TRAITS_H_
+
+#include <stddef.h>
+
+#include "base/compiler_specific.h"
+
+namespace base {
+
+// constexpr version of http://en.cppreference.com/w/cpp/string/char_traits.
+// This currently just implements the bits needed to support a (mostly)
+// constexpr StringPiece.
+//
+// TODO(dcheng): Once we switch to C++17, most methods will become constexpr and
+// we can switch over to using the one in the standard library.
+template <typename T>
+struct CharTraits {
+  // Performs a lexographical comparison of the first N characters of |s1| and
+  // |s2|. Returns 0 if equal, -1 if |s1| is less than |s2|, and 1 if |s1| is
+  // greater than |s2|.
+  static constexpr int compare(const T* s1, const T* s2, size_t n) noexcept;
+
+  // Returns the length of |s|, assuming null termination (and not including the
+  // terminating null).
+  static constexpr size_t length(const T* s) noexcept;
+};
+
+template <typename T>
+constexpr int CharTraits<T>::compare(const T* s1,
+                                     const T* s2,
+                                     size_t n) noexcept {
+  for (; n; --n, ++s1, ++s2) {
+    if (*s1 < *s2)
+      return -1;
+    if (*s1 > *s2)
+      return 1;
+  }
+  return 0;
+}
+
+template <typename T>
+constexpr size_t CharTraits<T>::length(const T* s) noexcept {
+  size_t i = 0;
+  for (; *s; ++s)
+    ++i;
+  return i;
+}
+
+// char specialization of CharTraits that can use clang's constexpr instrinsics,
+// where available.
+template <>
+struct CharTraits<char> {
+  static constexpr int compare(const char* s1,
+                               const char* s2,
+                               size_t n) noexcept;
+  static constexpr size_t length(const char* s) noexcept;
+};
+
+constexpr int CharTraits<char>::compare(const char* s1,
+                                        const char* s2,
+                                        size_t n) noexcept {
+#if HAS_FEATURE(cxx_constexpr_string_builtins)
+  return __builtin_memcmp(s1, s2, n);
+#else
+  for (; n; --n, ++s1, ++s2) {
+    if (*s1 < *s2)
+      return -1;
+    if (*s1 > *s2)
+      return 1;
+  }
+  return 0;
+#endif
+}
+
+constexpr size_t CharTraits<char>::length(const char* s) noexcept {
+#if defined(__clang__)
+  return __builtin_strlen(s);
+#else
+  size_t i = 0;
+  for (; *s; ++s)
+    ++i;
+  return i;
+#endif
+}
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_CHAR_TRAITS_H_
diff --git a/security/sandbox/chromium/base/strings/nullable_string16.cc b/security/sandbox/chromium/base/strings/nullable_string16.cc
new file mode 100644
index 0000000000..076b282eb1
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/nullable_string16.cc
@@ -0,0 +1,33 @@
+// 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.
+
+#include "base/strings/nullable_string16.h"
+
+#include <ostream>
+#include <utility>
+
+namespace base {
+NullableString16::NullableString16() = default;
+NullableString16::NullableString16(const NullableString16& other) = default;
+NullableString16::NullableString16(NullableString16&& other) = default;
+
+NullableString16::NullableString16(const string16& string, bool is_null) {
+  if (!is_null)
+    string_.emplace(string);
+}
+
+NullableString16::NullableString16(Optional<string16> optional_string16)
+    : string_(std::move(optional_string16)) {}
+
+NullableString16::~NullableString16() = default;
+NullableString16& NullableString16::operator=(const NullableString16& other) =
+    default;
+NullableString16& NullableString16::operator=(NullableString16&& other) =
+    default;
+
+std::ostream& operator<<(std::ostream& out, const NullableString16& value) {
+  return value.is_null() ? out << "(null)" : out << value.string();
+}
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/nullable_string16.h b/security/sandbox/chromium/base/strings/nullable_string16.h
new file mode 100644
index 0000000000..abddee0f74
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/nullable_string16.h
@@ -0,0 +1,55 @@
+// Copyright (c) 2010 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_NULLABLE_STRING16_H_
+#define BASE_STRINGS_NULLABLE_STRING16_H_
+
+#include <iosfwd>
+
+#include "base/base_export.h"
+#include "base/optional.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_util.h"
+
+namespace base {
+
+// This class is a simple wrapper for string16 which also contains a null
+// state.  This should be used only where the difference between null and
+// empty is meaningful.
+class BASE_EXPORT NullableString16 {
+ public:
+  NullableString16();
+  NullableString16(const NullableString16& other);
+  NullableString16(NullableString16&& other);
+  NullableString16(const string16& string, bool is_null);
+  explicit NullableString16(Optional<string16> optional_string16);
+  ~NullableString16();
+
+  NullableString16& operator=(const NullableString16& other);
+  NullableString16& operator=(NullableString16&& other);
+
+  const string16& string() const {
+    return string_ ? *string_ : EmptyString16();
+  }
+  bool is_null() const { return !string_; }
+  const Optional<string16>& as_optional_string16() const { return string_; }
+
+ private:
+  Optional<string16> string_;
+};
+
+inline bool operator==(const NullableString16& a, const NullableString16& b) {
+  return a.as_optional_string16() == b.as_optional_string16();
+}
+
+inline bool operator!=(const NullableString16& a, const NullableString16& b) {
+  return !(a == b);
+}
+
+BASE_EXPORT std::ostream& operator<<(std::ostream& out,
+                                     const NullableString16& value);
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_NULLABLE_STRING16_H_
diff --git a/security/sandbox/chromium/base/strings/safe_sprintf.cc b/security/sandbox/chromium/base/strings/safe_sprintf.cc
new file mode 100644
index 0000000000..89049abd79
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/safe_sprintf.cc
@@ -0,0 +1,682 @@
+// 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.
+
+#include "base/strings/safe_sprintf.h"
+
+#include <errno.h>
+#include <string.h>
+
+#include <algorithm>
+#include <limits>
+
+#include "base/macros.h"
+#include "build/build_config.h"
+
+#if !defined(NDEBUG)
+// In debug builds, we use RAW_CHECK() to print useful error messages, if
+// SafeSPrintf() is called with broken arguments.
+// As our contract promises that SafeSPrintf() can be called from any
+// restricted run-time context, it is not actually safe to call logging
+// functions from it; and we only ever do so for debug builds and hope for the
+// best. We should _never_ call any logging function other than RAW_CHECK(),
+// and we should _never_ include any logging code that is active in production
+// builds. Most notably, we should not include these logging functions in
+// unofficial release builds, even though those builds would otherwise have
+// DCHECKS() enabled.
+// In other words; please do not remove the #ifdef around this #include.
+// Instead, in production builds we opt for returning a degraded result,
+// whenever an error is encountered.
+// E.g. The broken function call
+//        SafeSPrintf("errno = %d (%x)", errno, strerror(errno))
+//      will print something like
+//        errno = 13, (%x)
+//      instead of
+//        errno = 13 (Access denied)
+//      In most of the anticipated use cases, that's probably the preferred
+//      behavior.
+#include "base/logging.h"
+#define DEBUG_CHECK RAW_CHECK
+#else
+#define DEBUG_CHECK(x) do { if (x) { } } while (0)
+#endif
+
+namespace base {
+namespace strings {
+
+// The code in this file is extremely careful to be async-signal-safe.
+//
+// Most obviously, we avoid calling any code that could dynamically allocate
+// memory. Doing so would almost certainly result in bugs and dead-locks.
+// We also avoid calling any other STL functions that could have unintended
+// side-effects involving memory allocation or access to other shared
+// resources.
+//
+// But on top of that, we also avoid calling other library functions, as many
+// of them have the side-effect of calling getenv() (in order to deal with
+// localization) or accessing errno. The latter sounds benign, but there are
+// several execution contexts where it isn't even possible to safely read let
+// alone write errno.
+//
+// The stated design goal of the SafeSPrintf() function is that it can be
+// called from any context that can safely call C or C++ code (i.e. anything
+// that doesn't require assembly code).
+//
+// For a brief overview of some but not all of the issues with async-signal-
+// safety, refer to:
+// http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html
+
+namespace {
+const size_t kSSizeMaxConst = ((size_t)(ssize_t)-1) >> 1;
+
+const char kUpCaseHexDigits[]   = "0123456789ABCDEF";
+const char kDownCaseHexDigits[] = "0123456789abcdef";
+}
+
+#if defined(NDEBUG)
+// We would like to define kSSizeMax as std::numeric_limits<ssize_t>::max(),
+// but C++ doesn't allow us to do that for constants. Instead, we have to
+// use careful casting and shifting. We later use a static_assert to
+// verify that this worked correctly.
+namespace {
+const size_t kSSizeMax = kSSizeMaxConst;
+}
+#else  // defined(NDEBUG)
+// For efficiency, we really need kSSizeMax to be a constant. But for unit
+// tests, it should be adjustable. This allows us to verify edge cases without
+// having to fill the entire available address space. As a compromise, we make
+// kSSizeMax adjustable in debug builds, and then only compile that particular
+// part of the unit test in debug builds.
+namespace {
+static size_t kSSizeMax = kSSizeMaxConst;
+}
+
+namespace internal {
+void SetSafeSPrintfSSizeMaxForTest(size_t max) {
+  kSSizeMax = max;
+}
+
+size_t GetSafeSPrintfSSizeMaxForTest() {
+  return kSSizeMax;
+}
+}
+#endif  // defined(NDEBUG)
+
+namespace {
+class Buffer {
+ public:
+  // |buffer| is caller-allocated storage that SafeSPrintf() writes to. It
+  // has |size| bytes of writable storage. It is the caller's responsibility
+  // to ensure that the buffer is at least one byte in size, so that it fits
+  // the trailing NUL that will be added by the destructor. The buffer also
+  // must be smaller or equal to kSSizeMax in size.
+  Buffer(char* buffer, size_t size)
+      : buffer_(buffer),
+        size_(size - 1),  // Account for trailing NUL byte
+        count_(0) {
+// MSVS2013's standard library doesn't mark max() as constexpr yet. cl.exe
+// supports static_cast but doesn't really implement constexpr yet so it doesn't
+// complain, but clang does.
+#if __cplusplus >= 201103 && !(defined(__clang__) && defined(OS_WIN))
+    static_assert(kSSizeMaxConst ==
+                      static_cast<size_t>(std::numeric_limits<ssize_t>::max()),
+                  "kSSizeMaxConst should be the max value of an ssize_t");
+#endif
+    DEBUG_CHECK(size > 0);
+    DEBUG_CHECK(size <= kSSizeMax);
+  }
+
+  ~Buffer() {
+    // The code calling the constructor guaranteed that there was enough space
+    // to store a trailing NUL -- and in debug builds, we are actually
+    // verifying this with DEBUG_CHECK()s in the constructor. So, we can
+    // always unconditionally write the NUL byte in the destructor.  We do not
+    // need to adjust the count_, as SafeSPrintf() copies snprintf() in not
+    // including the NUL byte in its return code.
+    *GetInsertionPoint() = '\000';
+  }
+
+  // Returns true, iff the buffer is filled all the way to |kSSizeMax-1|. The
+  // caller can now stop adding more data, as GetCount() has reached its
+  // maximum possible value.
+  inline bool OutOfAddressableSpace() const {
+    return count_ == static_cast<size_t>(kSSizeMax - 1);
+  }
+
+  // Returns the number of bytes that would have been emitted to |buffer_|
+  // if it was sized sufficiently large. This number can be larger than
+  // |size_|, if the caller provided an insufficiently large output buffer.
+  // But it will never be bigger than |kSSizeMax-1|.
+  inline ssize_t GetCount() const {
+    DEBUG_CHECK(count_ < kSSizeMax);
+    return static_cast<ssize_t>(count_);
+  }
+
+  // Emits one |ch| character into the |buffer_| and updates the |count_| of
+  // characters that are currently supposed to be in the buffer.
+  // Returns "false", iff the buffer was already full.
+  // N.B. |count_| increases even if no characters have been written. This is
+  // needed so that GetCount() can return the number of bytes that should
+  // have been allocated for the |buffer_|.
+  inline bool Out(char ch) {
+    if (size_ >= 1 && count_ < size_) {
+      buffer_[count_] = ch;
+      return IncrementCountByOne();
+    }
+    // |count_| still needs to be updated, even if the buffer has been
+    // filled completely. This allows SafeSPrintf() to return the number of
+    // bytes that should have been emitted.
+    IncrementCountByOne();
+    return false;
+  }
+
+  // Inserts |padding|-|len| bytes worth of padding into the |buffer_|.
+  // |count_| will also be incremented by the number of bytes that were meant
+  // to be emitted. The |pad| character is typically either a ' ' space
+  // or a '0' zero, but other non-NUL values are legal.
+  // Returns "false", iff the the |buffer_| filled up (i.e. |count_|
+  // overflowed |size_|) at any time during padding.
+  inline bool Pad(char pad, size_t padding, size_t len) {
+    DEBUG_CHECK(pad);
+    DEBUG_CHECK(padding <= kSSizeMax);
+    for (; padding > len; --padding) {
+      if (!Out(pad)) {
+        if (--padding) {
+          IncrementCount(padding-len);
+        }
+        return false;
+      }
+    }
+    return true;
+  }
+
+  // POSIX doesn't define any async-signal-safe function for converting
+  // an integer to ASCII. Define our own version.
+  //
+  // This also gives us the ability to make the function a little more
+  // powerful and have it deal with |padding|, with truncation, and with
+  // predicting the length of the untruncated output.
+  //
+  // IToASCII() converts an integer |i| to ASCII.
+  //
+  // Unlike similar functions in the standard C library, it never appends a
+  // NUL character. This is left for the caller to do.
+  //
+  // While the function signature takes a signed int64_t, the code decides at
+  // run-time whether to treat the argument as signed (int64_t) or as unsigned
+  // (uint64_t) based on the value of |sign|.
+  //
+  // It supports |base|s 2 through 16. Only a |base| of 10 is allowed to have
+  // a |sign|. Otherwise, |i| is treated as unsigned.
+  //
+  // For bases larger than 10, |upcase| decides whether lower-case or upper-
+  // case letters should be used to designate digits greater than 10.
+  //
+  // Padding can be done with either '0' zeros or ' ' spaces. Padding has to
+  // be positive and will always be applied to the left of the output.
+  //
+  // Prepends a |prefix| to the number (e.g. "0x"). This prefix goes to
+  // the left of |padding|, if |pad| is '0'; and to the right of |padding|
+  // if |pad| is ' '.
+  //
+  // Returns "false", if the |buffer_| overflowed at any time.
+  bool IToASCII(bool sign, bool upcase, int64_t i, int base,
+                char pad, size_t padding, const char* prefix);
+
+ private:
+  // Increments |count_| by |inc| unless this would cause |count_| to
+  // overflow |kSSizeMax-1|. Returns "false", iff an overflow was detected;
+  // it then clamps |count_| to |kSSizeMax-1|.
+  inline bool IncrementCount(size_t inc) {
+    // "inc" is either 1 or a "padding" value. Padding is clamped at
+    // run-time to at most kSSizeMax-1. So, we know that "inc" is always in
+    // the range 1..kSSizeMax-1.
+    // This allows us to compute "kSSizeMax - 1 - inc" without incurring any
+    // integer overflows.
+    DEBUG_CHECK(inc <= kSSizeMax - 1);
+    if (count_ > kSSizeMax - 1 - inc) {
+      count_ = kSSizeMax - 1;
+      return false;
+    }
+    count_ += inc;
+    return true;
+  }
+
+  // Convenience method for the common case of incrementing |count_| by one.
+  inline bool IncrementCountByOne() {
+    return IncrementCount(1);
+  }
+
+  // Return the current insertion point into the buffer. This is typically
+  // at |buffer_| + |count_|, but could be before that if truncation
+  // happened. It always points to one byte past the last byte that was
+  // successfully placed into the |buffer_|.
+  inline char* GetInsertionPoint() const {
+    size_t idx = count_;
+    if (idx > size_) {
+      idx = size_;
+    }
+    return buffer_ + idx;
+  }
+
+  // User-provided buffer that will receive the fully formatted output string.
+  char* buffer_;
+
+  // Number of bytes that are available in the buffer excluding the trailing
+  // NUL byte that will be added by the destructor.
+  const size_t size_;
+
+  // Number of bytes that would have been emitted to the buffer, if the buffer
+  // was sufficiently big. This number always excludes the trailing NUL byte
+  // and it is guaranteed to never grow bigger than kSSizeMax-1.
+  size_t count_;
+
+  DISALLOW_COPY_AND_ASSIGN(Buffer);
+};
+
+
+bool Buffer::IToASCII(bool sign, bool upcase, int64_t i, int base,
+                      char pad, size_t padding, const char* prefix) {
+  // Sanity check for parameters. None of these should ever fail, but see
+  // above for the rationale why we can't call CHECK().
+  DEBUG_CHECK(base >= 2);
+  DEBUG_CHECK(base <= 16);
+  DEBUG_CHECK(!sign || base == 10);
+  DEBUG_CHECK(pad == '0' || pad == ' ');
+  DEBUG_CHECK(padding <= kSSizeMax);
+  DEBUG_CHECK(!(sign && prefix && *prefix));
+
+  // Handle negative numbers, if the caller indicated that |i| should be
+  // treated as a signed number; otherwise treat |i| as unsigned (even if the
+  // MSB is set!)
+  // Details are tricky, because of limited data-types, but equivalent pseudo-
+  // code would look like:
+  //   if (sign && i < 0)
+  //     prefix = "-";
+  //   num = abs(i);
+  int minint = 0;
+  uint64_t num;
+  if (sign && i < 0) {
+    prefix = "-";
+
+    // Turn our number positive.
+    if (i == std::numeric_limits<int64_t>::min()) {
+      // The most negative integer needs special treatment.
+      minint = 1;
+      num = static_cast<uint64_t>(-(i + 1));
+    } else {
+      // "Normal" negative numbers are easy.
+      num = static_cast<uint64_t>(-i);
+    }
+  } else {
+    num = static_cast<uint64_t>(i);
+  }
+
+  // If padding with '0' zero, emit the prefix or '-' character now. Otherwise,
+  // make the prefix accessible in reverse order, so that we can later output
+  // it right between padding and the number.
+  // We cannot choose the easier approach of just reversing the number, as that
+  // fails in situations where we need to truncate numbers that have padding
+  // and/or prefixes.
+  const char* reverse_prefix = nullptr;
+  if (prefix && *prefix) {
+    if (pad == '0') {
+      while (*prefix) {
+        if (padding) {
+          --padding;
+        }
+        Out(*prefix++);
+      }
+      prefix = nullptr;
+    } else {
+      for (reverse_prefix = prefix; *reverse_prefix; ++reverse_prefix) {
+      }
+    }
+  } else
+    prefix = nullptr;
+  const size_t prefix_length = reverse_prefix - prefix;
+
+  // Loop until we have converted the entire number. Output at least one
+  // character (i.e. '0').
+  size_t start = count_;
+  size_t discarded = 0;
+  bool started = false;
+  do {
+    // Make sure there is still enough space left in our output buffer.
+    if (count_ >= size_) {
+      if (start < size_) {
+        // It is rare that we need to output a partial number. But if asked
+        // to do so, we will still make sure we output the correct number of
+        // leading digits.
+        // Since we are generating the digits in reverse order, we actually
+        // have to discard digits in the order that we have already emitted
+        // them. This is essentially equivalent to:
+        //   memmove(buffer_ + start, buffer_ + start + 1, size_ - start - 1)
+        for (char* move = buffer_ + start, *end = buffer_ + size_ - 1;
+             move < end;
+             ++move) {
+          *move = move[1];
+        }
+        ++discarded;
+        --count_;
+      } else if (count_ - size_ > 1) {
+        // Need to increment either |count_| or |discarded| to make progress.
+        // The latter is more efficient, as it eventually triggers fast
+        // handling of padding. But we have to ensure we don't accidentally
+        // change the overall state (i.e. switch the state-machine from
+        // discarding to non-discarding). |count_| needs to always stay
+        // bigger than |size_|.
+        --count_;
+        ++discarded;
+      }
+    }
+
+    // Output the next digit and (if necessary) compensate for the most
+    // negative integer needing special treatment. This works because,
+    // no matter the bit width of the integer, the lowest-most decimal
+    // integer always ends in 2, 4, 6, or 8.
+    if (!num && started) {
+      if (reverse_prefix > prefix) {
+        Out(*--reverse_prefix);
+      } else {
+        Out(pad);
+      }
+    } else {
+      started = true;
+      Out((upcase ? kUpCaseHexDigits : kDownCaseHexDigits)[num%base + minint]);
+    }
+
+    minint = 0;
+    num /= base;
+
+    // Add padding, if requested.
+    if (padding > 0) {
+      --padding;
+
+      // Performance optimization for when we are asked to output excessive
+      // padding, but our output buffer is limited in size.  Even if we output
+      // a 64bit number in binary, we would never write more than 64 plus
+      // prefix non-padding characters. So, once this limit has been passed,
+      // any further state change can be computed arithmetically; we know that
+      // by this time, our entire final output consists of padding characters
+      // that have all already been output.
+      if (discarded > 8*sizeof(num) + prefix_length) {
+        IncrementCount(padding);
+        padding = 0;
+      }
+    }
+  } while (num || padding || (reverse_prefix > prefix));
+
+  // Conversion to ASCII actually resulted in the digits being in reverse
+  // order. We can't easily generate them in forward order, as we can't tell
+  // the number of characters needed until we are done converting.
+  // So, now, we reverse the string (except for the possible '-' sign).
+  char* front = buffer_ + start;
+  char* back = GetInsertionPoint();
+  while (--back > front) {
+    char ch = *back;
+    *back = *front;
+    *front++ = ch;
+  }
+
+  IncrementCount(discarded);
+  return !discarded;
+}
+
+}  // anonymous namespace
+
+namespace internal {
+
+ssize_t SafeSNPrintf(char* buf, size_t sz, const char* fmt, const Arg* args,
+                     const size_t max_args) {
+  // Make sure that at least one NUL byte can be written, and that the buffer
+  // never overflows kSSizeMax. Not only does that use up most or all of the
+  // address space, it also would result in a return code that cannot be
+  // represented.
+  if (static_cast<ssize_t>(sz) < 1)
+    return -1;
+  sz = std::min(sz, kSSizeMax);
+
+  // Iterate over format string and interpret '%' arguments as they are
+  // encountered.
+  Buffer buffer(buf, sz);
+  size_t padding;
+  char pad;
+  for (unsigned int cur_arg = 0; *fmt && !buffer.OutOfAddressableSpace(); ) {
+    if (*fmt++ == '%') {
+      padding = 0;
+      pad = ' ';
+      char ch = *fmt++;
+    format_character_found:
+      switch (ch) {
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9':
+        // Found a width parameter. Convert to an integer value and store in
+        // "padding". If the leading digit is a zero, change the padding
+        // character from a space ' ' to a zero '0'.
+        pad = ch == '0' ? '0' : ' ';
+        for (;;) {
+          // The maximum allowed padding fills all the available address
+          // space and leaves just enough space to insert the trailing NUL.
+          const size_t max_padding = kSSizeMax - 1;
+          if (padding > max_padding/10 ||
+              10*padding > max_padding - (ch - '0')) {
+            DEBUG_CHECK(padding <= max_padding/10 &&
+                        10*padding <= max_padding - (ch - '0'));
+            // Integer overflow detected. Skip the rest of the width until
+            // we find the format character, then do the normal error handling.
+          padding_overflow:
+            padding = max_padding;
+            while ((ch = *fmt++) >= '0' && ch <= '9') {
+            }
+            if (cur_arg < max_args) {
+              ++cur_arg;
+            }
+            goto fail_to_expand;
+          }
+          padding = 10*padding + ch - '0';
+          if (padding > max_padding) {
+            // This doesn't happen for "sane" values of kSSizeMax. But once
+            // kSSizeMax gets smaller than about 10, our earlier range checks
+            // are incomplete. Unittests do trigger this artificial corner
+            // case.
+            DEBUG_CHECK(padding <= max_padding);
+            goto padding_overflow;
+          }
+          ch = *fmt++;
+          if (ch < '0' || ch > '9') {
+            // Reached the end of the width parameter. This is where the format
+            // character is found.
+            goto format_character_found;
+          }
+        }
+        break;
+      case 'c': {  // Output an ASCII character.
+        // Check that there are arguments left to be inserted.
+        if (cur_arg >= max_args) {
+          DEBUG_CHECK(cur_arg < max_args);
+          goto fail_to_expand;
+        }
+
+        // Check that the argument has the expected type.
+        const Arg& arg = args[cur_arg++];
+        if (arg.type != Arg::INT && arg.type != Arg::UINT) {
+          DEBUG_CHECK(arg.type == Arg::INT || arg.type == Arg::UINT);
+          goto fail_to_expand;
+        }
+
+        // Apply padding, if needed.
+        buffer.Pad(' ', padding, 1);
+
+        // Convert the argument to an ASCII character and output it.
+        char as_char = static_cast<char>(arg.integer.i);
+        if (!as_char) {
+          goto end_of_output_buffer;
+        }
+        buffer.Out(as_char);
+        break; }
+      case 'd':    // Output a possibly signed decimal value.
+      case 'o':    // Output an unsigned octal value.
+      case 'x':    // Output an unsigned hexadecimal value.
+      case 'X':
+      case 'p': {  // Output a pointer value.
+        // Check that there are arguments left to be inserted.
+        if (cur_arg >= max_args) {
+          DEBUG_CHECK(cur_arg < max_args);
+          goto fail_to_expand;
+        }
+
+        const Arg& arg = args[cur_arg++];
+        int64_t i;
+        const char* prefix = nullptr;
+        if (ch != 'p') {
+          // Check that the argument has the expected type.
+          if (arg.type != Arg::INT && arg.type != Arg::UINT) {
+            DEBUG_CHECK(arg.type == Arg::INT || arg.type == Arg::UINT);
+            goto fail_to_expand;
+          }
+          i = arg.integer.i;
+
+          if (ch != 'd') {
+            // The Arg() constructor automatically performed sign expansion on
+            // signed parameters. This is great when outputting a %d decimal
+            // number, but can result in unexpected leading 0xFF bytes when
+            // outputting a %x hexadecimal number. Mask bits, if necessary.
+            // We have to do this here, instead of in the Arg() constructor, as
+            // the Arg() constructor cannot tell whether we will output a %d
+            // or a %x. Only the latter should experience masking.
+            if (arg.integer.width < sizeof(int64_t)) {
+              i &= (1LL << (8*arg.integer.width)) - 1;
+            }
+          }
+        } else {
+          // Pointer values require an actual pointer or a string.
+          if (arg.type == Arg::POINTER) {
+            i = reinterpret_cast<uintptr_t>(arg.ptr);
+          } else if (arg.type == Arg::STRING) {
+            i = reinterpret_cast<uintptr_t>(arg.str);
+          } else if (arg.type == Arg::INT &&
+                     arg.integer.width == sizeof(NULL) &&
+                     arg.integer.i == 0) {  // Allow C++'s version of NULL
+            i = 0;
+          } else {
+            DEBUG_CHECK(arg.type == Arg::POINTER || arg.type == Arg::STRING);
+            goto fail_to_expand;
+          }
+
+          // Pointers always include the "0x" prefix.
+          prefix = "0x";
+        }
+
+        // Use IToASCII() to convert to ASCII representation. For decimal
+        // numbers, optionally print a sign. For hexadecimal numbers,
+        // distinguish between upper and lower case. %p addresses are always
+        // printed as upcase. Supports base 8, 10, and 16. Prints padding
+        // and/or prefixes, if so requested.
+        buffer.IToASCII(ch == 'd' && arg.type == Arg::INT,
+                        ch != 'x', i,
+                        ch == 'o' ? 8 : ch == 'd' ? 10 : 16,
+                        pad, padding, prefix);
+        break; }
+      case 's': {
+        // Check that there are arguments left to be inserted.
+        if (cur_arg >= max_args) {
+          DEBUG_CHECK(cur_arg < max_args);
+          goto fail_to_expand;
+        }
+
+        // Check that the argument has the expected type.
+        const Arg& arg = args[cur_arg++];
+        const char *s;
+        if (arg.type == Arg::STRING) {
+          s = arg.str ? arg.str : "<NULL>";
+        } else if (arg.type == Arg::INT && arg.integer.width == sizeof(NULL) &&
+                   arg.integer.i == 0) {  // Allow C++'s version of NULL
+          s = "<NULL>";
+        } else {
+          DEBUG_CHECK(arg.type == Arg::STRING);
+          goto fail_to_expand;
+        }
+
+        // Apply padding, if needed. This requires us to first check the
+        // length of the string that we are outputting.
+        if (padding) {
+          size_t len = 0;
+          for (const char* src = s; *src++; ) {
+            ++len;
+          }
+          buffer.Pad(' ', padding, len);
+        }
+
+        // Printing a string involves nothing more than copying it into the
+        // output buffer and making sure we don't output more bytes than
+        // available space; Out() takes care of doing that.
+        for (const char* src = s; *src; ) {
+          buffer.Out(*src++);
+        }
+        break; }
+      case '%':
+        // Quoted percent '%' character.
+        goto copy_verbatim;
+      fail_to_expand:
+        // C++ gives us tools to do type checking -- something that snprintf()
+        // could never really do. So, whenever we see arguments that don't
+        // match up with the format string, we refuse to output them. But
+        // since we have to be extremely conservative about being async-
+        // signal-safe, we are limited in the type of error handling that we
+        // can do in production builds (in debug builds we can use
+        // DEBUG_CHECK() and hope for the best). So, all we do is pass the
+        // format string unchanged. That should eventually get the user's
+        // attention; and in the meantime, it hopefully doesn't lose too much
+        // data.
+      default:
+        // Unknown or unsupported format character. Just copy verbatim to
+        // output.
+        buffer.Out('%');
+        DEBUG_CHECK(ch);
+        if (!ch) {
+          goto end_of_format_string;
+        }
+        buffer.Out(ch);
+        break;
+      }
+    } else {
+  copy_verbatim:
+    buffer.Out(fmt[-1]);
+    }
+  }
+ end_of_format_string:
+ end_of_output_buffer:
+  return buffer.GetCount();
+}
+
+}  // namespace internal
+
+ssize_t SafeSNPrintf(char* buf, size_t sz, const char* fmt) {
+  // Make sure that at least one NUL byte can be written, and that the buffer
+  // never overflows kSSizeMax. Not only does that use up most or all of the
+  // address space, it also would result in a return code that cannot be
+  // represented.
+  if (static_cast<ssize_t>(sz) < 1)
+    return -1;
+  sz = std::min(sz, kSSizeMax);
+
+  Buffer buffer(buf, sz);
+
+  // In the slow-path, we deal with errors by copying the contents of
+  // "fmt" unexpanded. This means, if there are no arguments passed, the
+  // SafeSPrintf() function always degenerates to a version of strncpy() that
+  // de-duplicates '%' characters.
+  const char* src = fmt;
+  for (; *src; ++src) {
+    buffer.Out(*src);
+    DEBUG_CHECK(src[0] != '%' || src[1] == '%');
+    if (src[0] == '%' && src[1] == '%') {
+      ++src;
+    }
+  }
+  return buffer.GetCount();
+}
+
+}  // namespace strings
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/safe_sprintf.h b/security/sandbox/chromium/base/strings/safe_sprintf.h
new file mode 100644
index 0000000000..01d649d07a
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/safe_sprintf.h
@@ -0,0 +1,246 @@
+// 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_SAFE_SPRINTF_H_
+#define BASE_STRINGS_SAFE_SPRINTF_H_
+
+#include "build/build_config.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#if defined(OS_POSIX) || defined(OS_FUCHSIA)
+// For ssize_t
+#include <unistd.h>
+#endif
+
+#include "base/base_export.h"
+
+namespace base {
+namespace strings {
+
+#if defined(COMPILER_MSVC)
+// Define ssize_t inside of our namespace.
+#if defined(_WIN64)
+typedef __int64 ssize_t;
+#else
+typedef long ssize_t;
+#endif
+#endif
+
+// SafeSPrintf() is a type-safe and completely self-contained version of
+// snprintf().
+//
+// SafeSNPrintf() is an alternative function signature that can be used when
+// not dealing with fixed-sized buffers. When possible, SafeSPrintf() should
+// always be used instead of SafeSNPrintf()
+//
+// These functions allow for formatting complicated messages from contexts that
+// require strict async-signal-safety. In fact, it is safe to call them from
+// any low-level execution context, as they are guaranteed to make no library
+// or system calls. It deliberately never touches "errno", either.
+//
+// The only exception to this rule is that in debug builds the code calls
+// RAW_CHECK() to help diagnose problems when the format string does not
+// match the rest of the arguments. In release builds, no CHECK()s are used,
+// and SafeSPrintf() instead returns an output string that expands only
+// those arguments that match their format characters. Mismatched arguments
+// are ignored.
+//
+// The code currently only supports a subset of format characters:
+//   %c, %o, %d, %x, %X, %p, and %s.
+//
+// SafeSPrintf() aims to be as liberal as reasonably possible. Integer-like
+// values of arbitrary width can be passed to all of the format characters
+// that expect integers. Thus, it is explicitly legal to pass an "int" to
+// "%c", and output will automatically look at the LSB only. It is also
+// explicitly legal to pass either signed or unsigned values, and the format
+// characters will automatically interpret the arguments accordingly.
+//
+// It is still not legal to mix-and-match integer-like values with pointer
+// values. For instance, you cannot pass a pointer to %x, nor can you pass an
+// integer to %p.
+//
+// The one exception is "0" zero being accepted by "%p". This works-around
+// the problem of C++ defining NULL as an integer-like value.
+//
+// All format characters take an optional width parameter. This must be a
+// positive integer. For %d, %o, %x, %X and %p, if the width starts with
+// a leading '0', padding is done with '0' instead of ' ' characters.
+//
+// There are a few features of snprintf()-style format strings, that
+// SafeSPrintf() does not support at this time.
+//
+// If an actual user showed up, there is no particularly strong reason they
+// couldn't be added. But that assumes that the trade-offs between complexity
+// and utility are favorable.
+//
+// For example, adding support for negative padding widths, and for %n are all
+// likely to be viewed positively. They are all clearly useful, low-risk, easy
+// to test, don't jeopardize the async-signal-safety of the code, and overall
+// have little impact on other parts of SafeSPrintf() function.
+//
+// On the other hands, adding support for alternate forms, positional
+// arguments, grouping, wide characters, localization or floating point numbers
+// are all unlikely to ever be added.
+//
+// SafeSPrintf() and SafeSNPrintf() mimic the behavior of snprintf() and they
+// return the number of bytes needed to store the untruncated output. This
+// does *not* include the terminating NUL byte.
+//
+// They return -1, iff a fatal error happened. This typically can only happen,
+// if the buffer size is a) negative, or b) zero (i.e. not even the NUL byte
+// can be written). The return value can never be larger than SSIZE_MAX-1.
+// This ensures that the caller can always add one to the signed return code
+// in order to determine the amount of storage that needs to be allocated.
+//
+// While the code supports type checking and while it is generally very careful
+// to avoid printing incorrect values, it tends to be conservative in printing
+// as much as possible, even when given incorrect parameters. Typically, in
+// case of an error, the format string will not be expanded. (i.e. something
+// like SafeSPrintf(buf, "%p %d", 1, 2) results in "%p 2"). See above for
+// the use of RAW_CHECK() in debug builds, though.
+//
+// Basic example:
+//   char buf[20];
+//   base::strings::SafeSPrintf(buf, "The answer: %2d", 42);
+//
+// Example with dynamically sized buffer (async-signal-safe). This code won't
+// work on Visual studio, as it requires dynamically allocating arrays on the
+// stack. Consider picking a smaller value for |kMaxSize| if stack size is
+// limited and known. On the other hand, if the parameters to SafeSNPrintf()
+// are trusted and not controllable by the user, you can consider eliminating
+// the check for |kMaxSize| altogether. The current value of SSIZE_MAX is
+// essentially a no-op that just illustrates how to implement an upper bound:
+//   const size_t kInitialSize = 128;
+//   const size_t kMaxSize = std::numeric_limits<ssize_t>::max();
+//   size_t size = kInitialSize;
+//   for (;;) {
+//     char buf[size];
+//     size = SafeSNPrintf(buf, size, "Error message \"%s\"\n", err) + 1;
+//     if (sizeof(buf) < kMaxSize && size > kMaxSize) {
+//       size = kMaxSize;
+//       continue;
+//     } else if (size > sizeof(buf))
+//       continue;
+//     write(2, buf, size-1);
+//     break;
+//   }
+
+namespace internal {
+// Helpers that use C++ overloading, templates, and specializations to deduce
+// and record type information from function arguments. This allows us to
+// later write a type-safe version of snprintf().
+
+struct Arg {
+  enum Type { INT, UINT, STRING, POINTER };
+
+  // Any integer-like value.
+  Arg(signed char c) : type(INT) {
+    integer.i = c;
+    integer.width = sizeof(char);
+  }
+  Arg(unsigned char c) : type(UINT) {
+    integer.i = c;
+    integer.width = sizeof(char);
+  }
+  Arg(signed short j) : type(INT) {
+    integer.i = j;
+    integer.width = sizeof(short);
+  }
+  Arg(unsigned short j) : type(UINT) {
+    integer.i = j;
+    integer.width = sizeof(short);
+  }
+  Arg(signed int j) : type(INT) {
+    integer.i = j;
+    integer.width = sizeof(int);
+  }
+  Arg(unsigned int j) : type(UINT) {
+    integer.i = j;
+    integer.width = sizeof(int);
+  }
+  Arg(signed long j) : type(INT) {
+    integer.i = j;
+    integer.width = sizeof(long);
+  }
+  Arg(unsigned long j) : type(UINT) {
+    integer.i = j;
+    integer.width = sizeof(long);
+  }
+  Arg(signed long long j) : type(INT) {
+    integer.i = j;
+    integer.width = sizeof(long long);
+  }
+  Arg(unsigned long long j) : type(UINT) {
+    integer.i = j;
+    integer.width = sizeof(long long);
+  }
+
+  // A C-style text string.
+  Arg(const char* s) : str(s), type(STRING) { }
+  Arg(char* s)       : str(s), type(STRING) { }
+
+  // Any pointer value that can be cast to a "void*".
+  template<class T> Arg(T* p) : ptr((void*)p), type(POINTER) { }
+
+  union {
+    // An integer-like value.
+    struct {
+      int64_t       i;
+      unsigned char width;
+    } integer;
+
+    // A C-style text string.
+    const char* str;
+
+    // A pointer to an arbitrary object.
+    const void* ptr;
+  };
+  const enum Type type;
+};
+
+// This is the internal function that performs the actual formatting of
+// an snprintf()-style format string.
+BASE_EXPORT ssize_t SafeSNPrintf(char* buf, size_t sz, const char* fmt,
+                                 const Arg* args, size_t max_args);
+
+#if !defined(NDEBUG)
+// In debug builds, allow unit tests to artificially lower the kSSizeMax
+// constant that is used as a hard upper-bound for all buffers. In normal
+// use, this constant should always be std::numeric_limits<ssize_t>::max().
+BASE_EXPORT void SetSafeSPrintfSSizeMaxForTest(size_t max);
+BASE_EXPORT size_t GetSafeSPrintfSSizeMaxForTest();
+#endif
+
+}  // namespace internal
+
+template<typename... Args>
+ssize_t SafeSNPrintf(char* buf, size_t N, const char* fmt, Args... args) {
+  // Use Arg() object to record type information and then copy arguments to an
+  // array to make it easier to iterate over them.
+  const internal::Arg arg_array[] = { args... };
+  return internal::SafeSNPrintf(buf, N, fmt, arg_array, sizeof...(args));
+}
+
+template<size_t N, typename... Args>
+ssize_t SafeSPrintf(char (&buf)[N], const char* fmt, Args... args) {
+  // Use Arg() object to record type information and then copy arguments to an
+  // array to make it easier to iterate over them.
+  const internal::Arg arg_array[] = { args... };
+  return internal::SafeSNPrintf(buf, N, fmt, arg_array, sizeof...(args));
+}
+
+// Fast-path when we don't actually need to substitute any arguments.
+BASE_EXPORT ssize_t SafeSNPrintf(char* buf, size_t N, const char* fmt);
+template<size_t N>
+inline ssize_t SafeSPrintf(char (&buf)[N], const char* fmt) {
+  return SafeSNPrintf(buf, N, fmt);
+}
+
+}  // namespace strings
+}  // namespace base
+
+#endif  // BASE_STRINGS_SAFE_SPRINTF_H_
diff --git a/security/sandbox/chromium/base/strings/safe_sprintf_unittest.cc b/security/sandbox/chromium/base/strings/safe_sprintf_unittest.cc
new file mode 100644
index 0000000000..bb9908f928
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/safe_sprintf_unittest.cc
@@ -0,0 +1,765 @@
+// 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.
+
+#include "base/strings/safe_sprintf.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <limits>
+#include <memory>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "build/build_config.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Death tests on Android are currently very flaky. No need to add more flaky
+// tests, as they just make it hard to spot real problems.
+// TODO(markus): See if the restrictions on Android can eventually be lifted.
+#if defined(GTEST_HAS_DEATH_TEST) && !defined(OS_ANDROID)
+#define ALLOW_DEATH_TEST
+#endif
+
+namespace base {
+namespace strings {
+
+TEST(SafeSPrintfTest, Empty) {
+  char buf[2] = { 'X', 'X' };
+
+  // Negative buffer size should always result in an error.
+  EXPECT_EQ(-1, SafeSNPrintf(buf, static_cast<size_t>(-1), ""));
+  EXPECT_EQ('X', buf[0]);
+  EXPECT_EQ('X', buf[1]);
+
+  // Zero buffer size should always result in an error.
+  EXPECT_EQ(-1, SafeSNPrintf(buf, 0, ""));
+  EXPECT_EQ('X', buf[0]);
+  EXPECT_EQ('X', buf[1]);
+
+  // A one-byte buffer should always print a single NUL byte.
+  EXPECT_EQ(0, SafeSNPrintf(buf, 1, ""));
+  EXPECT_EQ(0, buf[0]);
+  EXPECT_EQ('X', buf[1]);
+  buf[0] = 'X';
+
+  // A larger buffer should leave the trailing bytes unchanged.
+  EXPECT_EQ(0, SafeSNPrintf(buf, 2, ""));
+  EXPECT_EQ(0, buf[0]);
+  EXPECT_EQ('X', buf[1]);
+  buf[0] = 'X';
+
+  // The same test using SafeSPrintf() instead of SafeSNPrintf().
+  EXPECT_EQ(0, SafeSPrintf(buf, ""));
+  EXPECT_EQ(0, buf[0]);
+  EXPECT_EQ('X', buf[1]);
+  buf[0] = 'X';
+}
+
+TEST(SafeSPrintfTest, NoArguments) {
+  // Output a text message that doesn't require any substitutions. This
+  // is roughly equivalent to calling strncpy() (but unlike strncpy(), it does
+  // always add a trailing NUL; it always deduplicates '%' characters).
+  static const char text[] = "hello world";
+  char ref[20], buf[20];
+  memset(ref, 'X', sizeof(ref));
+  memcpy(buf, ref, sizeof(buf));
+
+  // A negative buffer size should always result in an error.
+  EXPECT_EQ(-1, SafeSNPrintf(buf, static_cast<size_t>(-1), text));
+  EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
+
+  // Zero buffer size should always result in an error.
+  EXPECT_EQ(-1, SafeSNPrintf(buf, 0, text));
+  EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
+
+  // A one-byte buffer should always print a single NUL byte.
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSNPrintf(buf, 1, text));
+  EXPECT_EQ(0, buf[0]);
+  EXPECT_TRUE(!memcmp(buf+1, ref+1, sizeof(buf)-1));
+  memcpy(buf, ref, sizeof(buf));
+
+  // A larger (but limited) buffer should always leave the trailing bytes
+  // unchanged.
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSNPrintf(buf, 2, text));
+  EXPECT_EQ(text[0], buf[0]);
+  EXPECT_EQ(0, buf[1]);
+  EXPECT_TRUE(!memcmp(buf+2, ref+2, sizeof(buf)-2));
+  memcpy(buf, ref, sizeof(buf));
+
+  // A unrestricted buffer length should always leave the trailing bytes
+  // unchanged.
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
+            SafeSNPrintf(buf, sizeof(buf), text));
+  EXPECT_EQ(std::string(text), std::string(buf));
+  EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
+                      sizeof(buf) - sizeof(text)));
+  memcpy(buf, ref, sizeof(buf));
+
+  // The same test using SafeSPrintf() instead of SafeSNPrintf().
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSPrintf(buf, text));
+  EXPECT_EQ(std::string(text), std::string(buf));
+  EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
+                      sizeof(buf) - sizeof(text)));
+  memcpy(buf, ref, sizeof(buf));
+
+  // Check for deduplication of '%' percent characters.
+  EXPECT_EQ(1, SafeSPrintf(buf, "%%"));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%%%"));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%X"));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%%%%X"));
+#if defined(NDEBUG)
+  EXPECT_EQ(1, SafeSPrintf(buf, "%"));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%%"));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%X"));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%%%X"));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, "%"), "src.1. == '%'");
+  EXPECT_DEATH(SafeSPrintf(buf, "%%%"), "src.1. == '%'");
+  EXPECT_DEATH(SafeSPrintf(buf, "%X"), "src.1. == '%'");
+  EXPECT_DEATH(SafeSPrintf(buf, "%%%X"), "src.1. == '%'");
+#endif
+}
+
+TEST(SafeSPrintfTest, OneArgument) {
+  // Test basic single-argument single-character substitution.
+  const char text[] = "hello world";
+  const char fmt[]  = "hello%cworld";
+  char ref[20], buf[20];
+  memset(ref, 'X', sizeof(buf));
+  memcpy(buf, ref, sizeof(buf));
+
+  // A negative buffer size should always result in an error.
+  EXPECT_EQ(-1, SafeSNPrintf(buf, static_cast<size_t>(-1), fmt, ' '));
+  EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
+
+  // Zero buffer size should always result in an error.
+  EXPECT_EQ(-1, SafeSNPrintf(buf, 0, fmt, ' '));
+  EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
+
+  // A one-byte buffer should always print a single NUL byte.
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
+            SafeSNPrintf(buf, 1, fmt, ' '));
+  EXPECT_EQ(0, buf[0]);
+  EXPECT_TRUE(!memcmp(buf+1, ref+1, sizeof(buf)-1));
+  memcpy(buf, ref, sizeof(buf));
+
+  // A larger (but limited) buffer should always leave the trailing bytes
+  // unchanged.
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
+            SafeSNPrintf(buf, 2, fmt, ' '));
+  EXPECT_EQ(text[0], buf[0]);
+  EXPECT_EQ(0, buf[1]);
+  EXPECT_TRUE(!memcmp(buf+2, ref+2, sizeof(buf)-2));
+  memcpy(buf, ref, sizeof(buf));
+
+  // A unrestricted buffer length should always leave the trailing bytes
+  // unchanged.
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
+            SafeSNPrintf(buf, sizeof(buf), fmt, ' '));
+  EXPECT_EQ(std::string(text), std::string(buf));
+  EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
+                      sizeof(buf) - sizeof(text)));
+  memcpy(buf, ref, sizeof(buf));
+
+  // The same test using SafeSPrintf() instead of SafeSNPrintf().
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSPrintf(buf, fmt, ' '));
+  EXPECT_EQ(std::string(text), std::string(buf));
+  EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
+                      sizeof(buf) - sizeof(text)));
+  memcpy(buf, ref, sizeof(buf));
+
+  // Check for deduplication of '%' percent characters.
+  EXPECT_EQ(1, SafeSPrintf(buf, "%%", 0));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%%%", 0));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%Y", 0));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%Y", 0));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%%%Y", 0));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%%%%Y", 0));
+#if defined(NDEBUG)
+  EXPECT_EQ(1, SafeSPrintf(buf, "%", 0));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%%", 0));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, "%", 0), "ch");
+  EXPECT_DEATH(SafeSPrintf(buf, "%%%", 0), "ch");
+#endif
+}
+
+TEST(SafeSPrintfTest, MissingArg) {
+#if defined(NDEBUG)
+  char buf[20];
+  EXPECT_EQ(3, SafeSPrintf(buf, "%c%c", 'A'));
+  EXPECT_EQ("A%c", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  char buf[20];
+  EXPECT_DEATH(SafeSPrintf(buf, "%c%c", 'A'), "cur_arg < max_args");
+#endif
+}
+
+TEST(SafeSPrintfTest, ASANFriendlyBufferTest) {
+  // Print into a buffer that is sized exactly to size. ASAN can verify that
+  // nobody attempts to write past the end of the buffer.
+  // There is a more complicated test in PrintLongString() that covers a lot
+  // more edge case, but it is also harder to debug in case of a failure.
+  const char kTestString[] = "This is a test";
+  std::unique_ptr<char[]> buf(new char[sizeof(kTestString)]);
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(kTestString) - 1),
+            SafeSNPrintf(buf.get(), sizeof(kTestString), kTestString));
+  EXPECT_EQ(std::string(kTestString), std::string(buf.get()));
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(kTestString) - 1),
+            SafeSNPrintf(buf.get(), sizeof(kTestString), "%s", kTestString));
+  EXPECT_EQ(std::string(kTestString), std::string(buf.get()));
+}
+
+TEST(SafeSPrintfTest, NArgs) {
+  // Pre-C++11 compilers have a different code path, that can only print
+  // up to ten distinct arguments.
+  // We test both SafeSPrintf() and SafeSNPrintf(). This makes sure we don't
+  // have typos in the copy-n-pasted code that is needed to deal with various
+  // numbers of arguments.
+  char buf[12];
+  EXPECT_EQ(1, SafeSPrintf(buf, "%c", 1));
+  EXPECT_EQ("\1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%c%c", 1, 2));
+  EXPECT_EQ("\1\2", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%c%c%c", 1, 2, 3));
+  EXPECT_EQ("\1\2\3", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%c%c%c%c", 1, 2, 3, 4));
+  EXPECT_EQ("\1\2\3\4", std::string(buf));
+  EXPECT_EQ(5, SafeSPrintf(buf, "%c%c%c%c%c", 1, 2, 3, 4, 5));
+  EXPECT_EQ("\1\2\3\4\5", std::string(buf));
+  EXPECT_EQ(6, SafeSPrintf(buf, "%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6));
+  EXPECT_EQ("\1\2\3\4\5\6", std::string(buf));
+  EXPECT_EQ(7, SafeSPrintf(buf, "%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7));
+  EXPECT_EQ("\1\2\3\4\5\6\7", std::string(buf));
+  EXPECT_EQ(8, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7, 8));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10", std::string(buf));
+  EXPECT_EQ(9, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c",
+                           1, 2, 3, 4, 5, 6, 7, 8, 9));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10\11", std::string(buf));
+  EXPECT_EQ(10, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c%c",
+                            1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
+
+  // Repeat all the tests with SafeSNPrintf() instead of SafeSPrintf().
+  EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12", std::string(buf));
+  EXPECT_EQ(1, SafeSNPrintf(buf, 11, "%c", 1));
+  EXPECT_EQ("\1", std::string(buf));
+  EXPECT_EQ(2, SafeSNPrintf(buf, 11, "%c%c", 1, 2));
+  EXPECT_EQ("\1\2", std::string(buf));
+  EXPECT_EQ(3, SafeSNPrintf(buf, 11, "%c%c%c", 1, 2, 3));
+  EXPECT_EQ("\1\2\3", std::string(buf));
+  EXPECT_EQ(4, SafeSNPrintf(buf, 11, "%c%c%c%c", 1, 2, 3, 4));
+  EXPECT_EQ("\1\2\3\4", std::string(buf));
+  EXPECT_EQ(5, SafeSNPrintf(buf, 11, "%c%c%c%c%c", 1, 2, 3, 4, 5));
+  EXPECT_EQ("\1\2\3\4\5", std::string(buf));
+  EXPECT_EQ(6, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6));
+  EXPECT_EQ("\1\2\3\4\5\6", std::string(buf));
+  EXPECT_EQ(7, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7));
+  EXPECT_EQ("\1\2\3\4\5\6\7", std::string(buf));
+  EXPECT_EQ(8, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c",
+                            1, 2, 3, 4, 5, 6, 7, 8));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10", std::string(buf));
+  EXPECT_EQ(9, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c%c",
+                            1, 2, 3, 4, 5, 6, 7, 8, 9));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10\11", std::string(buf));
+  EXPECT_EQ(10, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c%c%c",
+                             1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12", std::string(buf));
+
+  EXPECT_EQ(11, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c%c%c",
+                            1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12\13", std::string(buf));
+  EXPECT_EQ(11, SafeSNPrintf(buf, 12, "%c%c%c%c%c%c%c%c%c%c%c",
+                             1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11));
+  EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12\13", std::string(buf));
+}
+
+TEST(SafeSPrintfTest, DataTypes) {
+  char buf[40];
+
+  // Bytes
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint8_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%d", (uint8_t)-1));
+  EXPECT_EQ("255", std::string(buf));
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int8_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int8_t)-1));
+  EXPECT_EQ("-1", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%d", (int8_t)-128));
+  EXPECT_EQ("-128", std::string(buf));
+
+  // Half-words
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint16_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(5, SafeSPrintf(buf, "%d", (uint16_t)-1));
+  EXPECT_EQ("65535", std::string(buf));
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int16_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int16_t)-1));
+  EXPECT_EQ("-1", std::string(buf));
+  EXPECT_EQ(6, SafeSPrintf(buf, "%d", (int16_t)-32768));
+  EXPECT_EQ("-32768", std::string(buf));
+
+  // Words
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint32_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(10, SafeSPrintf(buf, "%d", (uint32_t)-1));
+  EXPECT_EQ("4294967295", std::string(buf));
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int32_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int32_t)-1));
+  EXPECT_EQ("-1", std::string(buf));
+  // Work-around for an limitation of C90
+  EXPECT_EQ(11, SafeSPrintf(buf, "%d", (int32_t)-2147483647-1));
+  EXPECT_EQ("-2147483648", std::string(buf));
+
+  // Quads
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint64_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(20, SafeSPrintf(buf, "%d", (uint64_t)-1));
+  EXPECT_EQ("18446744073709551615", std::string(buf));
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int64_t)1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int64_t)-1));
+  EXPECT_EQ("-1", std::string(buf));
+  // Work-around for an limitation of C90
+  EXPECT_EQ(20, SafeSPrintf(buf, "%d", (int64_t)-9223372036854775807LL-1));
+  EXPECT_EQ("-9223372036854775808", std::string(buf));
+
+  // Strings (both const and mutable).
+  EXPECT_EQ(4, SafeSPrintf(buf, "test"));
+  EXPECT_EQ("test", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, buf));
+  EXPECT_EQ("test", std::string(buf));
+
+  // Pointer
+  char addr[20];
+  sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)buf);
+  SafeSPrintf(buf, "%p", buf);
+  EXPECT_EQ(std::string(addr), std::string(buf));
+  SafeSPrintf(buf, "%p", (const char *)buf);
+  EXPECT_EQ(std::string(addr), std::string(buf));
+  sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)sprintf);
+  SafeSPrintf(buf, "%p", sprintf);
+  EXPECT_EQ(std::string(addr), std::string(buf));
+
+  // Padding for pointers is a little more complicated because of the "0x"
+  // prefix. Padding with '0' zeros is relatively straight-forward, but
+  // padding with ' ' spaces requires more effort.
+  sprintf(addr, "0x%017llX", (unsigned long long)(uintptr_t)buf);
+  SafeSPrintf(buf, "%019p", buf);
+  EXPECT_EQ(std::string(addr), std::string(buf));
+  sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)buf);
+  memset(addr, ' ',
+         (char*)memmove(addr + sizeof(addr) - strlen(addr) - 1,
+                        addr, strlen(addr)+1) - addr);
+  SafeSPrintf(buf, "%19p", buf);
+  EXPECT_EQ(std::string(addr), std::string(buf));
+}
+
+namespace {
+void PrintLongString(char* buf, size_t sz) {
+  // Output a reasonably complex expression into a limited-size buffer.
+  // At least one byte is available for writing the NUL character.
+  CHECK_GT(sz, static_cast<size_t>(0));
+
+  // Allocate slightly more space, so that we can verify that SafeSPrintf()
+  // never writes past the end of the buffer.
+  std::unique_ptr<char[]> tmp(new char[sz + 2]);
+  memset(tmp.get(), 'X', sz+2);
+
+  // Use SafeSPrintf() to output a complex list of arguments:
+  // - test padding and truncating %c single characters.
+  // - test truncating %s simple strings.
+  // - test mismatching arguments and truncating (for %d != %s).
+  // - test zero-padding and truncating %x hexadecimal numbers.
+  // - test outputting and truncating %d MININT.
+  // - test outputting and truncating %p arbitrary pointer values.
+  // - test outputting, padding and truncating NULL-pointer %s strings.
+  char* out = tmp.get();
+  size_t out_sz = sz;
+  size_t len;
+  for (std::unique_ptr<char[]> perfect_buf;;) {
+    size_t needed =
+        SafeSNPrintf(out, out_sz,
+#if defined(NDEBUG)
+                     "A%2cong %s: %d %010X %d %p%7s", 'l', "string", "",
+#else
+                     "A%2cong %s: %%d %010X %d %p%7s", 'l', "string",
+#endif
+                     0xDEADBEEF, std::numeric_limits<intptr_t>::min(),
+                     PrintLongString, static_cast<char*>(nullptr)) +
+        1;
+
+    // Various sanity checks:
+    // The numbered of characters needed to print the full string should always
+    // be bigger or equal to the bytes that have actually been output.
+    len = strlen(tmp.get());
+    CHECK_GE(needed, len+1);
+
+    // The number of characters output should always fit into the buffer that
+    // was passed into SafeSPrintf().
+    CHECK_LT(len, out_sz);
+
+    // The output is always terminated with a NUL byte (actually, this test is
+    // always going to pass, as strlen() already verified this)
+    EXPECT_FALSE(tmp[len]);
+
+    // ASAN can check that we are not overwriting buffers, iff we make sure the
+    // buffer is exactly the size that we are expecting to be written. After
+    // running SafeSNPrintf() the first time, it is possible to compute the
+    // correct buffer size for this test. So, allocate a second buffer and run
+    // the exact same SafeSNPrintf() command again.
+    if (!perfect_buf.get()) {
+      out_sz = std::min(needed, sz);
+      out = new char[out_sz];
+      perfect_buf.reset(out);
+    } else {
+      break;
+    }
+  }
+
+  // All trailing bytes are unchanged.
+  for (size_t i = len+1; i < sz+2; ++i)
+    EXPECT_EQ('X', tmp[i]);
+
+  // The text that was generated by SafeSPrintf() should always match the
+  // equivalent text generated by sprintf(). Please note that the format
+  // string for sprintf() is not complicated, as it does not have the
+  // benefit of getting type information from the C++ compiler.
+  //
+  // N.B.: It would be so much cleaner to use snprintf(). But unfortunately,
+  //       Visual Studio doesn't support this function, and the work-arounds
+  //       are all really awkward.
+  char ref[256];
+  CHECK_LE(sz, sizeof(ref));
+  sprintf(ref, "A long string: %%d 00DEADBEEF %lld 0x%llX <NULL>",
+          static_cast<long long>(std::numeric_limits<intptr_t>::min()),
+          static_cast<unsigned long long>(
+            reinterpret_cast<uintptr_t>(PrintLongString)));
+  ref[sz-1] = '\000';
+
+#if defined(NDEBUG)
+  const size_t kSSizeMax = std::numeric_limits<ssize_t>::max();
+#else
+  const size_t kSSizeMax = internal::GetSafeSPrintfSSizeMaxForTest();
+#endif
+
+  // Compare the output from SafeSPrintf() to the one from sprintf().
+  EXPECT_EQ(std::string(ref).substr(0, kSSizeMax-1), std::string(tmp.get()));
+
+  // We allocated a slightly larger buffer, so that we could perform some
+  // extra sanity checks. Now that the tests have all passed, we copy the
+  // data to the output buffer that the caller provided.
+  memcpy(buf, tmp.get(), len+1);
+}
+
+#if !defined(NDEBUG)
+class ScopedSafeSPrintfSSizeMaxSetter {
+ public:
+  ScopedSafeSPrintfSSizeMaxSetter(size_t sz) {
+    old_ssize_max_ = internal::GetSafeSPrintfSSizeMaxForTest();
+    internal::SetSafeSPrintfSSizeMaxForTest(sz);
+  }
+
+  ~ScopedSafeSPrintfSSizeMaxSetter() {
+    internal::SetSafeSPrintfSSizeMaxForTest(old_ssize_max_);
+  }
+
+ private:
+  size_t old_ssize_max_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedSafeSPrintfSSizeMaxSetter);
+};
+#endif
+
+}  // anonymous namespace
+
+TEST(SafeSPrintfTest, Truncation) {
+  // We use PrintLongString() to print a complex long string and then
+  // truncate to all possible lengths. This ends up exercising a lot of
+  // different code paths in SafeSPrintf() and IToASCII(), as truncation can
+  // happen in a lot of different states.
+  char ref[256];
+  PrintLongString(ref, sizeof(ref));
+  for (size_t i = strlen(ref)+1; i; --i) {
+    char buf[sizeof(ref)];
+    PrintLongString(buf, i);
+    EXPECT_EQ(std::string(ref, i - 1), std::string(buf));
+  }
+
+  // When compiling in debug mode, we have the ability to fake a small
+  // upper limit for the maximum value that can be stored in an ssize_t.
+  // SafeSPrintf() uses this upper limit to determine how many bytes it will
+  // write to the buffer, even if the caller claimed a bigger buffer size.
+  // Repeat the truncation test and verify that this other code path in
+  // SafeSPrintf() works correctly, too.
+#if !defined(NDEBUG)
+  for (size_t i = strlen(ref)+1; i > 1; --i) {
+    ScopedSafeSPrintfSSizeMaxSetter ssize_max_setter(i);
+    char buf[sizeof(ref)];
+    PrintLongString(buf, sizeof(buf));
+    EXPECT_EQ(std::string(ref, i - 1), std::string(buf));
+  }
+
+  // kSSizeMax is also used to constrain the maximum amount of padding, before
+  // SafeSPrintf() detects an error in the format string.
+  ScopedSafeSPrintfSSizeMaxSetter ssize_max_setter(100);
+  char buf[256];
+  EXPECT_EQ(99, SafeSPrintf(buf, "%99c", ' '));
+  EXPECT_EQ(std::string(99, ' '), std::string(buf));
+  *buf = '\000';
+#if defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, "%100c", ' '), "padding <= max_padding");
+#endif
+  EXPECT_EQ(0, *buf);
+#endif
+}
+
+TEST(SafeSPrintfTest, Padding) {
+  char buf[40], fmt[40];
+
+  // Chars %c
+  EXPECT_EQ(1, SafeSPrintf(buf, "%c", 'A'));
+  EXPECT_EQ("A", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%2c", 'A'));
+  EXPECT_EQ(" A", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%02c", 'A'));
+  EXPECT_EQ(" A", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%-2c", 'A'));
+  EXPECT_EQ("%-2c", std::string(buf));
+  SafeSPrintf(fmt, "%%%dc", std::numeric_limits<ssize_t>::max() - 1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1, SafeSPrintf(buf, fmt, 'A'));
+  SafeSPrintf(fmt, "%%%dc",
+              static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, fmt, 'A'));
+  EXPECT_EQ("%c", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, fmt, 'A'), "padding <= max_padding");
+#endif
+
+  // Octal %o
+  EXPECT_EQ(1, SafeSPrintf(buf, "%o", 1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%2o", 1));
+  EXPECT_EQ(" 1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%02o", 1));
+  EXPECT_EQ("01", std::string(buf));
+  EXPECT_EQ(12, SafeSPrintf(buf, "%12o", -1));
+  EXPECT_EQ(" 37777777777", std::string(buf));
+  EXPECT_EQ(12, SafeSPrintf(buf, "%012o", -1));
+  EXPECT_EQ("037777777777", std::string(buf));
+  EXPECT_EQ(23, SafeSPrintf(buf, "%23o", -1LL));
+  EXPECT_EQ(" 1777777777777777777777", std::string(buf));
+  EXPECT_EQ(23, SafeSPrintf(buf, "%023o", -1LL));
+  EXPECT_EQ("01777777777777777777777", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%2o", 0111));
+  EXPECT_EQ("111", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%-2o", 1));
+  EXPECT_EQ("%-2o", std::string(buf));
+  SafeSPrintf(fmt, "%%%do", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, 1));
+  EXPECT_EQ("   ", std::string(buf));
+  SafeSPrintf(fmt, "%%0%do", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, 1));
+  EXPECT_EQ("000", std::string(buf));
+  SafeSPrintf(fmt, "%%%do",
+              static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
+  EXPECT_EQ("%o", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
+#endif
+
+  // Decimals %d
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", 1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%2d", 1));
+  EXPECT_EQ(" 1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%02d", 1));
+  EXPECT_EQ("01", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%3d", -1));
+  EXPECT_EQ(" -1", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%03d", -1));
+  EXPECT_EQ("-01", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%2d", 111));
+  EXPECT_EQ("111", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%2d", -111));
+  EXPECT_EQ("-111", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%-2d", 1));
+  EXPECT_EQ("%-2d", std::string(buf));
+  SafeSPrintf(fmt, "%%%dd", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, 1));
+  EXPECT_EQ("   ", std::string(buf));
+  SafeSPrintf(fmt, "%%0%dd", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, 1));
+  EXPECT_EQ("000", std::string(buf));
+  SafeSPrintf(fmt, "%%%dd",
+              static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
+  EXPECT_EQ("%d", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
+#endif
+
+  // Hex %X
+  EXPECT_EQ(1, SafeSPrintf(buf, "%X", 1));
+  EXPECT_EQ("1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%2X", 1));
+  EXPECT_EQ(" 1", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%02X", 1));
+  EXPECT_EQ("01", std::string(buf));
+  EXPECT_EQ(9, SafeSPrintf(buf, "%9X", -1));
+  EXPECT_EQ(" FFFFFFFF", std::string(buf));
+  EXPECT_EQ(9, SafeSPrintf(buf, "%09X", -1));
+  EXPECT_EQ("0FFFFFFFF", std::string(buf));
+  EXPECT_EQ(17, SafeSPrintf(buf, "%17X", -1LL));
+  EXPECT_EQ(" FFFFFFFFFFFFFFFF", std::string(buf));
+  EXPECT_EQ(17, SafeSPrintf(buf, "%017X", -1LL));
+  EXPECT_EQ("0FFFFFFFFFFFFFFFF", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%2X", 0x111));
+  EXPECT_EQ("111", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%-2X", 1));
+  EXPECT_EQ("%-2X", std::string(buf));
+  SafeSPrintf(fmt, "%%%dX", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, 1));
+  EXPECT_EQ("   ", std::string(buf));
+  SafeSPrintf(fmt, "%%0%dX", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, 1));
+  EXPECT_EQ("000", std::string(buf));
+  SafeSPrintf(fmt, "%%%dX",
+              static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
+  EXPECT_EQ("%X", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
+#endif
+
+  // Pointer %p
+  EXPECT_EQ(3, SafeSPrintf(buf, "%p", (void*)1));
+  EXPECT_EQ("0x1", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%4p", (void*)1));
+  EXPECT_EQ(" 0x1", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%04p", (void*)1));
+  EXPECT_EQ("0x01", std::string(buf));
+  EXPECT_EQ(5, SafeSPrintf(buf, "%4p", (void*)0x111));
+  EXPECT_EQ("0x111", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%-2p", (void*)1));
+  EXPECT_EQ("%-2p", std::string(buf));
+  SafeSPrintf(fmt, "%%%dp", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, (void*)1));
+  EXPECT_EQ("   ", std::string(buf));
+  SafeSPrintf(fmt, "%%0%dp", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, (void*)1));
+  EXPECT_EQ("0x0", std::string(buf));
+  SafeSPrintf(fmt, "%%%dp",
+              static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
+  EXPECT_EQ("%p", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
+#endif
+
+  // String
+  EXPECT_EQ(1, SafeSPrintf(buf, "%s", "A"));
+  EXPECT_EQ("A", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%2s", "A"));
+  EXPECT_EQ(" A", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%02s", "A"));
+  EXPECT_EQ(" A", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%2s", "AAA"));
+  EXPECT_EQ("AAA", std::string(buf));
+  EXPECT_EQ(4, SafeSPrintf(buf, "%-2s", "A"));
+  EXPECT_EQ("%-2s", std::string(buf));
+  SafeSPrintf(fmt, "%%%ds", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, "A"));
+  EXPECT_EQ("   ", std::string(buf));
+  SafeSPrintf(fmt, "%%0%ds", std::numeric_limits<ssize_t>::max()-1);
+  EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
+            SafeSNPrintf(buf, 4, fmt, "A"));
+  EXPECT_EQ("   ", std::string(buf));
+  SafeSPrintf(fmt, "%%%ds",
+              static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, fmt, "A"));
+  EXPECT_EQ("%s", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, fmt, "A"), "padding <= max_padding");
+#endif
+}
+
+TEST(SafeSPrintfTest, EmbeddedNul) {
+  char buf[] = { 'X', 'X', 'X', 'X' };
+  EXPECT_EQ(2, SafeSPrintf(buf, "%3c", 0));
+  EXPECT_EQ(' ', buf[0]);
+  EXPECT_EQ(' ', buf[1]);
+  EXPECT_EQ(0,   buf[2]);
+  EXPECT_EQ('X', buf[3]);
+
+  // Check handling of a NUL format character. N.B. this takes two different
+  // code paths depending on whether we are actually passing arguments. If
+  // we don't have any arguments, we are running in the fast-path code, that
+  // looks (almost) like a strncpy().
+#if defined(NDEBUG)
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%%"));
+  EXPECT_EQ("%%", std::string(buf));
+  EXPECT_EQ(2, SafeSPrintf(buf, "%%%", 0));
+  EXPECT_EQ("%%", std::string(buf));
+#elif defined(ALLOW_DEATH_TEST)
+  EXPECT_DEATH(SafeSPrintf(buf, "%%%"), "src.1. == '%'");
+  EXPECT_DEATH(SafeSPrintf(buf, "%%%", 0), "ch");
+#endif
+}
+
+TEST(SafeSPrintfTest, EmitNULL) {
+  char buf[40];
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion-null"
+#endif
+  EXPECT_EQ(1, SafeSPrintf(buf, "%d", NULL));
+  EXPECT_EQ("0", std::string(buf));
+  EXPECT_EQ(3, SafeSPrintf(buf, "%p", NULL));
+  EXPECT_EQ("0x0", std::string(buf));
+  EXPECT_EQ(6, SafeSPrintf(buf, "%s", NULL));
+  EXPECT_EQ("<NULL>", std::string(buf));
+#if defined(__GCC__)
+#pragma GCC diagnostic pop
+#endif
+}
+
+TEST(SafeSPrintfTest, PointerSize) {
+  // The internal data representation is a 64bit value, independent of the
+  // native word size. We want to perform sign-extension for signed integers,
+  // but we want to avoid doing so for pointer types. This could be a
+  // problem on systems, where pointers are only 32bit. This tests verifies
+  // that there is no such problem.
+  char *str = reinterpret_cast<char *>(0x80000000u);
+  void *ptr = str;
+  char buf[40];
+  EXPECT_EQ(10, SafeSPrintf(buf, "%p", str));
+  EXPECT_EQ("0x80000000", std::string(buf));
+  EXPECT_EQ(10, SafeSPrintf(buf, "%p", ptr));
+  EXPECT_EQ("0x80000000", std::string(buf));
+}
+
+}  // namespace strings
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/string16.cc b/security/sandbox/chromium/base/strings/string16.cc
new file mode 100644
index 0000000000..84962e6710
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string16.cc
@@ -0,0 +1,87 @@
+// 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.
+
+#include "base/strings/string16.h"
+
+#if defined(WCHAR_T_IS_UTF16) && !defined(_AIX)
+
+#error This file should not be used on 2-byte wchar_t systems
+// If this winds up being needed on 2-byte wchar_t systems, either the
+// definitions below can be used, or the host system's wide character
+// functions like wmemcmp can be wrapped.
+
+#elif defined(WCHAR_T_IS_UTF32)
+
+#include <ostream>
+
+#include "base/strings/string_piece.h"
+
+namespace base {
+
+int c16memcmp(const char16* s1, const char16* s2, size_t n) {
+  // We cannot call memcmp because that changes the semantics.
+  while (n-- > 0) {
+    if (*s1 != *s2) {
+      // We cannot use (*s1 - *s2) because char16 is unsigned.
+      return ((*s1 < *s2) ? -1 : 1);
+    }
+    ++s1;
+    ++s2;
+  }
+  return 0;
+}
+
+size_t c16len(const char16* s) {
+  const char16 *s_orig = s;
+  while (*s) {
+    ++s;
+  }
+  return s - s_orig;
+}
+
+const char16* c16memchr(const char16* s, char16 c, size_t n) {
+  while (n-- > 0) {
+    if (*s == c) {
+      return s;
+    }
+    ++s;
+  }
+  return nullptr;
+}
+
+char16* c16memmove(char16* s1, const char16* s2, size_t n) {
+  return static_cast<char16*>(memmove(s1, s2, n * sizeof(char16)));
+}
+
+char16* c16memcpy(char16* s1, const char16* s2, size_t n) {
+  return static_cast<char16*>(memcpy(s1, s2, n * sizeof(char16)));
+}
+
+char16* c16memset(char16* s, char16 c, size_t n) {
+  char16 *s_orig = s;
+  while (n-- > 0) {
+    *s = c;
+    ++s;
+  }
+  return s_orig;
+}
+
+namespace string16_internals {
+
+std::ostream& operator<<(std::ostream& out, const string16& str) {
+  return out << base::StringPiece16(str);
+}
+
+void PrintTo(const string16& str, std::ostream* out) {
+  *out << str;
+}
+
+}  // namespace string16_internals
+
+}  // namespace base
+
+template class std::
+    basic_string<base::char16, base::string16_internals::string16_char_traits>;
+
+#endif  // WCHAR_T_IS_UTF32
diff --git a/security/sandbox/chromium/base/strings/string16.h b/security/sandbox/chromium/base/strings/string16.h
new file mode 100644
index 0000000000..3cb6c7c495
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string16.h
@@ -0,0 +1,229 @@
+// 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_STRING16_H_
+#define BASE_STRINGS_STRING16_H_
+
+// WHAT:
+// A version of std::basic_string that provides 2-byte characters even when
+// wchar_t is not implemented as a 2-byte type. You can access this class as
+// string16. We also define char16, which string16 is based upon.
+//
+// WHY:
+// On Windows, wchar_t is 2 bytes, and it can conveniently handle UTF-16/UCS-2
+// data. Plenty of existing code operates on strings encoded as UTF-16.
+//
+// On many other platforms, sizeof(wchar_t) is 4 bytes by default. We can make
+// it 2 bytes by using the GCC flag -fshort-wchar. But then std::wstring fails
+// at run time, because it calls some functions (like wcslen) that come from
+// the system's native C library -- which was built with a 4-byte wchar_t!
+// It's wasteful to use 4-byte wchar_t strings to carry UTF-16 data, and it's
+// entirely improper on those systems where the encoding of wchar_t is defined
+// as UTF-32.
+//
+// Here, we define string16, which is similar to std::wstring but replaces all
+// libc functions with custom, 2-byte-char compatible routines. It is capable
+// of carrying UTF-16-encoded data.
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include <functional>
+#include <string>
+
+#include "base/base_export.h"
+#include "build/build_config.h"
+
+#if defined(WCHAR_T_IS_UTF16)
+
+// Define a macro for wrapping construction of char16 arrays and string16s from
+// a literal string. This indirection allows for an easier migration of
+// base::char16 to char16_t on platforms where WCHAR_T_IS_UTF16, as only a one
+// character change to the macro will be necessary.
+// This macro does not exist when WCHAR_T_IS_UTF32, as it is currently not
+// possible to create a char array form a literal in this case.
+// TODO(https://crbug.com/911896): Remove this macro once base::char16 is
+// char16_t on all platforms.
+#define STRING16_LITERAL(x) L##x
+
+namespace base {
+
+typedef wchar_t char16;
+typedef std::wstring string16;
+
+}  // namespace base
+
+#elif defined(WCHAR_T_IS_UTF32)
+
+#include <wchar.h>  // for mbstate_t
+
+namespace base {
+
+typedef uint16_t char16;
+
+// char16 versions of the functions required by string16_char_traits; these
+// are based on the wide character functions of similar names ("w" or "wcs"
+// instead of "c16").
+BASE_EXPORT int c16memcmp(const char16* s1, const char16* s2, size_t n);
+BASE_EXPORT size_t c16len(const char16* s);
+BASE_EXPORT const char16* c16memchr(const char16* s, char16 c, size_t n);
+BASE_EXPORT char16* c16memmove(char16* s1, const char16* s2, size_t n);
+BASE_EXPORT char16* c16memcpy(char16* s1, const char16* s2, size_t n);
+BASE_EXPORT char16* c16memset(char16* s, char16 c, size_t n);
+
+// This namespace contains the implementation of base::string16 along with
+// things that need to be found via argument-dependent lookup from a
+// base::string16.
+namespace string16_internals {
+
+struct string16_char_traits {
+  typedef char16 char_type;
+  typedef int int_type;
+
+  // int_type needs to be able to hold each possible value of char_type, and in
+  // addition, the distinct value of eof().
+  static_assert(sizeof(int_type) > sizeof(char_type),
+                "int must be larger than 16 bits wide");
+
+  typedef std::streamoff off_type;
+  typedef mbstate_t state_type;
+  typedef std::fpos<state_type> pos_type;
+
+  static void assign(char_type& c1, const char_type& c2) {
+    c1 = c2;
+  }
+
+  static bool eq(const char_type& c1, const char_type& c2) {
+    return c1 == c2;
+  }
+  static bool lt(const char_type& c1, const char_type& c2) {
+    return c1 < c2;
+  }
+
+  static int compare(const char_type* s1, const char_type* s2, size_t n) {
+    return c16memcmp(s1, s2, n);
+  }
+
+  static size_t length(const char_type* s) {
+    return c16len(s);
+  }
+
+  static const char_type* find(const char_type* s, size_t n,
+                               const char_type& a) {
+    return c16memchr(s, a, n);
+  }
+
+  static char_type* move(char_type* s1, const char_type* s2, size_t n) {
+    return c16memmove(s1, s2, n);
+  }
+
+  static char_type* copy(char_type* s1, const char_type* s2, size_t n) {
+    return c16memcpy(s1, s2, n);
+  }
+
+  static char_type* assign(char_type* s, size_t n, char_type a) {
+    return c16memset(s, a, n);
+  }
+
+  static int_type not_eof(const int_type& c) {
+    return eq_int_type(c, eof()) ? 0 : c;
+  }
+
+  static char_type to_char_type(const int_type& c) {
+    return char_type(c);
+  }
+
+  static int_type to_int_type(const char_type& c) {
+    return int_type(c);
+  }
+
+  static bool eq_int_type(const int_type& c1, const int_type& c2) {
+    return c1 == c2;
+  }
+
+  static int_type eof() {
+    return static_cast<int_type>(EOF);
+  }
+};
+
+}  // namespace string16_internals
+
+typedef std::basic_string<char16,
+                          base::string16_internals::string16_char_traits>
+    string16;
+
+namespace string16_internals {
+
+BASE_EXPORT extern std::ostream& operator<<(std::ostream& out,
+                                            const string16& str);
+
+// This is required by googletest to print a readable output on test failures.
+BASE_EXPORT extern void PrintTo(const string16& str, std::ostream* out);
+
+}  // namespace string16_internals
+
+}  // namespace base
+
+// The string class will be explicitly instantiated only once, in string16.cc.
+//
+// std::basic_string<> in GNU libstdc++ contains a static data member,
+// _S_empty_rep_storage, to represent empty strings.  When an operation such
+// as assignment or destruction is performed on a string, causing its existing
+// data member to be invalidated, it must not be freed if this static data
+// member is being used.  Otherwise, it counts as an attempt to free static
+// (and not allocated) data, which is a memory error.
+//
+// Generally, due to C++ template magic, _S_empty_rep_storage will be marked
+// as a coalesced symbol, meaning that the linker will combine multiple
+// instances into a single one when generating output.
+//
+// If a string class is used by multiple shared libraries, a problem occurs.
+// Each library will get its own copy of _S_empty_rep_storage.  When strings
+// are passed across a library boundary for alteration or destruction, memory
+// errors will result.  GNU libstdc++ contains a configuration option,
+// --enable-fully-dynamic-string (_GLIBCXX_FULLY_DYNAMIC_STRING), which
+// disables the static data member optimization, but it's a good optimization
+// and non-STL code is generally at the mercy of the system's STL
+// configuration.  Fully-dynamic strings are not the default for GNU libstdc++
+// libstdc++ itself or for the libstdc++ installations on the systems we care
+// about, such as Mac OS X and relevant flavors of Linux.
+//
+// See also http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24196 .
+//
+// To avoid problems, string classes need to be explicitly instantiated only
+// once, in exactly one library.  All other string users see it via an "extern"
+// declaration.  This is precisely how GNU libstdc++ handles
+// std::basic_string<char> (string) and std::basic_string<wchar_t> (wstring).
+//
+// This also works around a Mac OS X linker bug in ld64-85.2.1 (Xcode 3.1.2),
+// in which the linker does not fully coalesce symbols when dead code
+// stripping is enabled.  This bug causes the memory errors described above
+// to occur even when a std::basic_string<> does not cross shared library
+// boundaries, such as in statically-linked executables.
+//
+// TODO(mark): File this bug with Apple and update this note with a bug number.
+
+extern template class BASE_EXPORT
+    std::basic_string<base::char16,
+                      base::string16_internals::string16_char_traits>;
+
+// Specialize std::hash for base::string16. Although the style guide forbids
+// this in general, it is necessary for consistency with WCHAR_T_IS_UTF16
+// platforms, where base::string16 is a type alias for std::wstring.
+namespace std {
+template <>
+struct hash<base::string16> {
+  std::size_t operator()(const base::string16& s) const {
+    std::size_t result = 0;
+    for (base::char16 c : s)
+      result = (result * 131) + c;
+    return result;
+  }
+};
+}  // namespace std
+
+#endif  // WCHAR_T_IS_UTF32
+
+#endif  // BASE_STRINGS_STRING16_H_
diff --git a/security/sandbox/chromium/base/strings/string_number_conversions.cc b/security/sandbox/chromium/base/strings/string_number_conversions.cc
new file mode 100644
index 0000000000..8b71b0ae11
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_number_conversions.cc
@@ -0,0 +1,545 @@
+// 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/strings/string_number_conversions.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <wctype.h>
+
+#include <limits>
+#include <type_traits>
+
+#include "base/logging.h"
+#include "base/no_destructor.h"
+#include "base/numerics/safe_math.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/third_party/double_conversion/double-conversion/double-conversion.h"
+
+namespace base {
+
+namespace {
+
+template <typename STR, typename INT>
+struct IntToStringT {
+  static STR IntToString(INT value) {
+    // log10(2) ~= 0.3 bytes needed per bit or per byte log10(2**8) ~= 2.4.
+    // So round up to allocate 3 output characters per byte, plus 1 for '-'.
+    const size_t kOutputBufSize =
+        3 * sizeof(INT) + std::numeric_limits<INT>::is_signed;
+
+    // Create the string in a temporary buffer, write it back to front, and
+    // then return the substr of what we ended up using.
+    using CHR = typename STR::value_type;
+    CHR outbuf[kOutputBufSize];
+
+    // The ValueOrDie call below can never fail, because UnsignedAbs is valid
+    // for all valid inputs.
+    typename std::make_unsigned<INT>::type res =
+        CheckedNumeric<INT>(value).UnsignedAbs().ValueOrDie();
+
+    CHR* end = outbuf + kOutputBufSize;
+    CHR* i = end;
+    do {
+      --i;
+      DCHECK(i != outbuf);
+      *i = static_cast<CHR>((res % 10) + '0');
+      res /= 10;
+    } while (res != 0);
+    if (IsValueNegative(value)) {
+      --i;
+      DCHECK(i != outbuf);
+      *i = static_cast<CHR>('-');
+    }
+    return STR(i, end);
+  }
+};
+
+// Utility to convert a character to a digit in a given base
+template<typename CHAR, int BASE, bool BASE_LTE_10> class BaseCharToDigit {
+};
+
+// Faster specialization for bases <= 10
+template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, true> {
+ public:
+  static bool Convert(CHAR c, uint8_t* digit) {
+    if (c >= '0' && c < '0' + BASE) {
+      *digit = static_cast<uint8_t>(c - '0');
+      return true;
+    }
+    return false;
+  }
+};
+
+// Specialization for bases where 10 < base <= 36
+template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, false> {
+ public:
+  static bool Convert(CHAR c, uint8_t* digit) {
+    if (c >= '0' && c <= '9') {
+      *digit = c - '0';
+    } else if (c >= 'a' && c < 'a' + BASE - 10) {
+      *digit = c - 'a' + 10;
+    } else if (c >= 'A' && c < 'A' + BASE - 10) {
+      *digit = c - 'A' + 10;
+    } else {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <int BASE, typename CHAR>
+bool CharToDigit(CHAR c, uint8_t* digit) {
+  return BaseCharToDigit<CHAR, BASE, BASE <= 10>::Convert(c, digit);
+}
+
+// There is an IsUnicodeWhitespace for wchars defined in string_util.h, but it
+// is locale independent, whereas the functions we are replacing were
+// locale-dependent. TBD what is desired, but for the moment let's not
+// introduce a change in behaviour.
+template<typename CHAR> class WhitespaceHelper {
+};
+
+template<> class WhitespaceHelper<char> {
+ public:
+  static bool Invoke(char c) {
+    return 0 != isspace(static_cast<unsigned char>(c));
+  }
+};
+
+template<> class WhitespaceHelper<char16> {
+ public:
+  static bool Invoke(char16 c) {
+    return 0 != iswspace(c);
+  }
+};
+
+template<typename CHAR> bool LocalIsWhitespace(CHAR c) {
+  return WhitespaceHelper<CHAR>::Invoke(c);
+}
+
+// IteratorRangeToNumberTraits should provide:
+//  - a typedef for iterator_type, the iterator type used as input.
+//  - a typedef for value_type, the target numeric type.
+//  - static functions min, max (returning the minimum and maximum permitted
+//    values)
+//  - constant kBase, the base in which to interpret the input
+template<typename IteratorRangeToNumberTraits>
+class IteratorRangeToNumber {
+ public:
+  typedef IteratorRangeToNumberTraits traits;
+  typedef typename traits::iterator_type const_iterator;
+  typedef typename traits::value_type value_type;
+
+  // Generalized iterator-range-to-number conversion.
+  //
+  static bool Invoke(const_iterator begin,
+                     const_iterator end,
+                     value_type* output) {
+    bool valid = true;
+
+    while (begin != end && LocalIsWhitespace(*begin)) {
+      valid = false;
+      ++begin;
+    }
+
+    if (begin != end && *begin == '-') {
+      if (!std::numeric_limits<value_type>::is_signed) {
+        *output = 0;
+        valid = false;
+      } else if (!Negative::Invoke(begin + 1, end, output)) {
+        valid = false;
+      }
+    } else {
+      if (begin != end && *begin == '+') {
+        ++begin;
+      }
+      if (!Positive::Invoke(begin, end, output)) {
+        valid = false;
+      }
+    }
+
+    return valid;
+  }
+
+ private:
+  // Sign provides:
+  //  - a static function, CheckBounds, that determines whether the next digit
+  //    causes an overflow/underflow
+  //  - a static function, Increment, that appends the next digit appropriately
+  //    according to the sign of the number being parsed.
+  template<typename Sign>
+  class Base {
+   public:
+    static bool Invoke(const_iterator begin, const_iterator end,
+                       typename traits::value_type* output) {
+      *output = 0;
+
+      if (begin == end) {
+        return false;
+      }
+
+      // Note: no performance difference was found when using template
+      // specialization to remove this check in bases other than 16
+      if (traits::kBase == 16 && end - begin > 2 && *begin == '0' &&
+          (*(begin + 1) == 'x' || *(begin + 1) == 'X')) {
+        begin += 2;
+      }
+
+      for (const_iterator current = begin; current != end; ++current) {
+        uint8_t new_digit = 0;
+
+        if (!CharToDigit<traits::kBase>(*current, &new_digit)) {
+          return false;
+        }
+
+        if (current != begin) {
+          if (!Sign::CheckBounds(output, new_digit)) {
+            return false;
+          }
+          *output *= traits::kBase;
+        }
+
+        Sign::Increment(new_digit, output);
+      }
+      return true;
+    }
+  };
+
+  class Positive : public Base<Positive> {
+   public:
+    static bool CheckBounds(value_type* output, uint8_t new_digit) {
+      if (*output > static_cast<value_type>(traits::max() / traits::kBase) ||
+          (*output == static_cast<value_type>(traits::max() / traits::kBase) &&
+           new_digit > traits::max() % traits::kBase)) {
+        *output = traits::max();
+        return false;
+      }
+      return true;
+    }
+    static void Increment(uint8_t increment, value_type* output) {
+      *output += increment;
+    }
+  };
+
+  class Negative : public Base<Negative> {
+   public:
+    static bool CheckBounds(value_type* output, uint8_t new_digit) {
+      if (*output < traits::min() / traits::kBase ||
+          (*output == traits::min() / traits::kBase &&
+           new_digit > 0 - traits::min() % traits::kBase)) {
+        *output = traits::min();
+        return false;
+      }
+      return true;
+    }
+    static void Increment(uint8_t increment, value_type* output) {
+      *output -= increment;
+    }
+  };
+};
+
+template<typename ITERATOR, typename VALUE, int BASE>
+class BaseIteratorRangeToNumberTraits {
+ public:
+  typedef ITERATOR iterator_type;
+  typedef VALUE value_type;
+  static value_type min() {
+    return std::numeric_limits<value_type>::min();
+  }
+  static value_type max() {
+    return std::numeric_limits<value_type>::max();
+  }
+  static const int kBase = BASE;
+};
+
+template<typename ITERATOR>
+class BaseHexIteratorRangeToIntTraits
+    : public BaseIteratorRangeToNumberTraits<ITERATOR, int, 16> {
+};
+
+template <typename ITERATOR>
+class BaseHexIteratorRangeToUIntTraits
+    : public BaseIteratorRangeToNumberTraits<ITERATOR, uint32_t, 16> {};
+
+template <typename ITERATOR>
+class BaseHexIteratorRangeToInt64Traits
+    : public BaseIteratorRangeToNumberTraits<ITERATOR, int64_t, 16> {};
+
+template <typename ITERATOR>
+class BaseHexIteratorRangeToUInt64Traits
+    : public BaseIteratorRangeToNumberTraits<ITERATOR, uint64_t, 16> {};
+
+typedef BaseHexIteratorRangeToIntTraits<StringPiece::const_iterator>
+    HexIteratorRangeToIntTraits;
+
+typedef BaseHexIteratorRangeToUIntTraits<StringPiece::const_iterator>
+    HexIteratorRangeToUIntTraits;
+
+typedef BaseHexIteratorRangeToInt64Traits<StringPiece::const_iterator>
+    HexIteratorRangeToInt64Traits;
+
+typedef BaseHexIteratorRangeToUInt64Traits<StringPiece::const_iterator>
+    HexIteratorRangeToUInt64Traits;
+
+template <typename VALUE, int BASE>
+class StringPieceToNumberTraits
+    : public BaseIteratorRangeToNumberTraits<StringPiece::const_iterator,
+                                             VALUE,
+                                             BASE> {
+};
+
+template <typename VALUE>
+bool StringToIntImpl(StringPiece input, VALUE* output) {
+  return IteratorRangeToNumber<StringPieceToNumberTraits<VALUE, 10> >::Invoke(
+      input.begin(), input.end(), output);
+}
+
+template <typename VALUE, int BASE>
+class StringPiece16ToNumberTraits
+    : public BaseIteratorRangeToNumberTraits<StringPiece16::const_iterator,
+                                             VALUE,
+                                             BASE> {
+};
+
+template <typename VALUE>
+bool String16ToIntImpl(StringPiece16 input, VALUE* output) {
+  return IteratorRangeToNumber<StringPiece16ToNumberTraits<VALUE, 10> >::Invoke(
+      input.begin(), input.end(), output);
+}
+
+}  // namespace
+
+std::string NumberToString(int value) {
+  return IntToStringT<std::string, int>::IntToString(value);
+}
+
+string16 NumberToString16(int value) {
+  return IntToStringT<string16, int>::IntToString(value);
+}
+
+std::string NumberToString(unsigned value) {
+  return IntToStringT<std::string, unsigned>::IntToString(value);
+}
+
+string16 NumberToString16(unsigned value) {
+  return IntToStringT<string16, unsigned>::IntToString(value);
+}
+
+std::string NumberToString(long value) {
+  return IntToStringT<std::string, long>::IntToString(value);
+}
+
+string16 NumberToString16(long value) {
+  return IntToStringT<string16, long>::IntToString(value);
+}
+
+std::string NumberToString(unsigned long value) {
+  return IntToStringT<std::string, unsigned long>::IntToString(value);
+}
+
+string16 NumberToString16(unsigned long value) {
+  return IntToStringT<string16, unsigned long>::IntToString(value);
+}
+
+std::string NumberToString(long long value) {
+  return IntToStringT<std::string, long long>::IntToString(value);
+}
+
+string16 NumberToString16(long long value) {
+  return IntToStringT<string16, long long>::IntToString(value);
+}
+
+std::string NumberToString(unsigned long long value) {
+  return IntToStringT<std::string, unsigned long long>::IntToString(value);
+}
+
+string16 NumberToString16(unsigned long long value) {
+  return IntToStringT<string16, unsigned long long>::IntToString(value);
+}
+
+static const double_conversion::DoubleToStringConverter*
+GetDoubleToStringConverter() {
+  static NoDestructor<double_conversion::DoubleToStringConverter> converter(
+      double_conversion::DoubleToStringConverter::EMIT_POSITIVE_EXPONENT_SIGN,
+      nullptr, nullptr, 'e', -6, 12, 0, 0);
+  return converter.get();
+}
+
+std::string NumberToString(double value) {
+  char buffer[32];
+  double_conversion::StringBuilder builder(buffer, sizeof(buffer));
+  GetDoubleToStringConverter()->ToShortest(value, &builder);
+  return std::string(buffer, builder.position());
+}
+
+base::string16 NumberToString16(double value) {
+  char buffer[32];
+  double_conversion::StringBuilder builder(buffer, sizeof(buffer));
+  GetDoubleToStringConverter()->ToShortest(value, &builder);
+
+  // The number will be ASCII. This creates the string using the "input
+  // iterator" variant which promotes from 8-bit to 16-bit via "=".
+  return base::string16(&buffer[0], &buffer[builder.position()]);
+}
+
+bool StringToInt(StringPiece input, int* output) {
+  return StringToIntImpl(input, output);
+}
+
+bool StringToInt(StringPiece16 input, int* output) {
+  return String16ToIntImpl(input, output);
+}
+
+bool StringToUint(StringPiece input, unsigned* output) {
+  return StringToIntImpl(input, output);
+}
+
+bool StringToUint(StringPiece16 input, unsigned* output) {
+  return String16ToIntImpl(input, output);
+}
+
+bool StringToInt64(StringPiece input, int64_t* output) {
+  return StringToIntImpl(input, output);
+}
+
+bool StringToInt64(StringPiece16 input, int64_t* output) {
+  return String16ToIntImpl(input, output);
+}
+
+bool StringToUint64(StringPiece input, uint64_t* output) {
+  return StringToIntImpl(input, output);
+}
+
+bool StringToUint64(StringPiece16 input, uint64_t* output) {
+  return String16ToIntImpl(input, output);
+}
+
+bool StringToSizeT(StringPiece input, size_t* output) {
+  return StringToIntImpl(input, output);
+}
+
+bool StringToSizeT(StringPiece16 input, size_t* output) {
+  return String16ToIntImpl(input, output);
+}
+
+template <typename STRING, typename CHAR>
+bool StringToDoubleImpl(STRING input, const CHAR* data, double* output) {
+  static NoDestructor<double_conversion::StringToDoubleConverter> converter(
+      double_conversion::StringToDoubleConverter::ALLOW_LEADING_SPACES |
+          double_conversion::StringToDoubleConverter::ALLOW_TRAILING_JUNK,
+      0.0, 0, nullptr, nullptr);
+
+  int processed_characters_count;
+  *output = converter->StringToDouble(data, input.size(),
+                                      &processed_characters_count);
+
+  // Cases to return false:
+  //  - If the input string is empty, there was nothing to parse.
+  //  - If the value saturated to HUGE_VAL.
+  //  - If the entire string was not processed, there are either characters
+  //    remaining in the string after a parsed number, or the string does not
+  //    begin with a parseable number.
+  //  - If the first character is a space, there was leading whitespace
+  return !input.empty() && *output != HUGE_VAL && *output != -HUGE_VAL &&
+         static_cast<size_t>(processed_characters_count) == input.size() &&
+         !IsUnicodeWhitespace(input[0]);
+}
+
+bool StringToDouble(StringPiece input, double* output) {
+  return StringToDoubleImpl(input, input.data(), output);
+}
+
+bool StringToDouble(StringPiece16 input, double* output) {
+  return StringToDoubleImpl(
+      input, reinterpret_cast<const uint16_t*>(input.data()), output);
+}
+
+std::string HexEncode(const void* bytes, size_t size) {
+  static const char kHexChars[] = "0123456789ABCDEF";
+
+  // Each input byte creates two output hex characters.
+  std::string ret(size * 2, '\0');
+
+  for (size_t i = 0; i < size; ++i) {
+    char b = reinterpret_cast<const char*>(bytes)[i];
+    ret[(i * 2)] = kHexChars[(b >> 4) & 0xf];
+    ret[(i * 2) + 1] = kHexChars[b & 0xf];
+  }
+  return ret;
+}
+
+std::string HexEncode(base::span<const uint8_t> bytes) {
+  return HexEncode(bytes.data(), bytes.size());
+}
+
+bool HexStringToInt(StringPiece input, int* output) {
+  return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke(
+    input.begin(), input.end(), output);
+}
+
+bool HexStringToUInt(StringPiece input, uint32_t* output) {
+  return IteratorRangeToNumber<HexIteratorRangeToUIntTraits>::Invoke(
+      input.begin(), input.end(), output);
+}
+
+bool HexStringToInt64(StringPiece input, int64_t* output) {
+  return IteratorRangeToNumber<HexIteratorRangeToInt64Traits>::Invoke(
+    input.begin(), input.end(), output);
+}
+
+bool HexStringToUInt64(StringPiece input, uint64_t* output) {
+  return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke(
+      input.begin(), input.end(), output);
+}
+
+template <typename Container>
+static bool HexStringToByteContainer(StringPiece input, Container* output) {
+  DCHECK_EQ(output->size(), 0u);
+  size_t count = input.size();
+  if (count == 0 || (count % 2) != 0)
+    return false;
+  for (uintptr_t i = 0; i < count / 2; ++i) {
+    uint8_t msb = 0;  // most significant 4 bits
+    uint8_t lsb = 0;  // least significant 4 bits
+    if (!CharToDigit<16>(input[i * 2], &msb) ||
+        !CharToDigit<16>(input[i * 2 + 1], &lsb)) {
+      return false;
+    }
+    output->push_back((msb << 4) | lsb);
+  }
+  return true;
+}
+
+bool HexStringToBytes(StringPiece input, std::vector<uint8_t>* output) {
+  return HexStringToByteContainer(input, output);
+}
+
+bool HexStringToString(StringPiece input, std::string* output) {
+  return HexStringToByteContainer(input, output);
+}
+
+bool HexStringToSpan(StringPiece input, base::span<uint8_t> output) {
+  size_t count = input.size();
+  if (count == 0 || (count % 2) != 0)
+    return false;
+
+  if (count / 2 != output.size())
+    return false;
+
+  for (uintptr_t i = 0; i < count / 2; ++i) {
+    uint8_t msb = 0;  // most significant 4 bits
+    uint8_t lsb = 0;  // least significant 4 bits
+    if (!CharToDigit<16>(input[i * 2], &msb) ||
+        !CharToDigit<16>(input[i * 2 + 1], &lsb)) {
+      return false;
+    }
+    output[i] = (msb << 4) | lsb;
+  }
+  return true;
+}
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/string_number_conversions.h b/security/sandbox/chromium/base/strings/string_number_conversions.h
new file mode 100644
index 0000000000..87df24e21c
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_number_conversions.h
@@ -0,0 +1,157 @@
+// 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.
+
+#ifndef BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_
+#define BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/containers/span.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
+#include "build/build_config.h"
+
+// ----------------------------------------------------------------------------
+// IMPORTANT MESSAGE FROM YOUR SPONSOR
+//
+// This file contains no "wstring" variants. New code should use string16. If
+// you need to make old code work, use the UTF8 version and convert. Please do
+// not add wstring variants.
+//
+// Please do not add "convenience" functions for converting strings to integers
+// that return the value and ignore success/failure. That encourages people to
+// write code that doesn't properly handle the error conditions.
+//
+// DO NOT use these functions in any UI unless it's NOT localized on purpose.
+// Instead, use base::MessageFormatter for a complex message with numbers
+// (integer, float, double) embedded or base::Format{Number,Double,Percent} to
+// just format a single number/percent. Note that some languages use native
+// digits instead of ASCII digits while others use a group separator or decimal
+// point different from ',' and '.'. Using these functions in the UI would lead
+// numbers to be formatted in a non-native way.
+// ----------------------------------------------------------------------------
+
+namespace base {
+
+// Number -> string conversions ------------------------------------------------
+
+// Ignores locale! see warning above.
+BASE_EXPORT std::string NumberToString(int value);
+BASE_EXPORT string16 NumberToString16(int value);
+BASE_EXPORT std::string NumberToString(unsigned int value);
+BASE_EXPORT string16 NumberToString16(unsigned int value);
+BASE_EXPORT std::string NumberToString(long value);
+BASE_EXPORT string16 NumberToString16(long value);
+BASE_EXPORT std::string NumberToString(unsigned long value);
+BASE_EXPORT string16 NumberToString16(unsigned long value);
+BASE_EXPORT std::string NumberToString(long long value);
+BASE_EXPORT string16 NumberToString16(long long value);
+BASE_EXPORT std::string NumberToString(unsigned long long value);
+BASE_EXPORT string16 NumberToString16(unsigned long long value);
+BASE_EXPORT std::string NumberToString(double value);
+BASE_EXPORT string16 NumberToString16(double value);
+
+// String -> number conversions ------------------------------------------------
+
+// Perform a best-effort conversion of the input string to a numeric type,
+// setting |*output| to the result of the conversion.  Returns true for
+// "perfect" conversions; returns false in the following cases:
+//  - Overflow. |*output| will be set to the maximum value supported
+//    by the data type.
+//  - Underflow. |*output| will be set to the minimum value supported
+//    by the data type.
+//  - Trailing characters in the string after parsing the number.  |*output|
+//    will be set to the value of the number that was parsed.
+//  - Leading whitespace in the string before parsing the number. |*output| will
+//    be set to the value of the number that was parsed.
+//  - No characters parseable as a number at the beginning of the string.
+//    |*output| will be set to 0.
+//  - Empty string.  |*output| will be set to 0.
+// WARNING: Will write to |output| even when returning false.
+//          Read the comments above carefully.
+BASE_EXPORT bool StringToInt(StringPiece input, int* output);
+BASE_EXPORT bool StringToInt(StringPiece16 input, int* output);
+
+BASE_EXPORT bool StringToUint(StringPiece input, unsigned* output);
+BASE_EXPORT bool StringToUint(StringPiece16 input, unsigned* output);
+
+BASE_EXPORT bool StringToInt64(StringPiece input, int64_t* output);
+BASE_EXPORT bool StringToInt64(StringPiece16 input, int64_t* output);
+
+BASE_EXPORT bool StringToUint64(StringPiece input, uint64_t* output);
+BASE_EXPORT bool StringToUint64(StringPiece16 input, uint64_t* output);
+
+BASE_EXPORT bool StringToSizeT(StringPiece input, size_t* output);
+BASE_EXPORT bool StringToSizeT(StringPiece16 input, size_t* output);
+
+// For floating-point conversions, only conversions of input strings in decimal
+// form are defined to work.  Behavior with strings representing floating-point
+// numbers in hexadecimal, and strings representing non-finite values (such as
+// NaN and inf) is undefined.  Otherwise, these behave the same as the integral
+// variants.  This expects the input string to NOT be specific to the locale.
+// If your input is locale specific, use ICU to read the number.
+// WARNING: Will write to |output| even when returning false.
+//          Read the comments here and above StringToInt() carefully.
+BASE_EXPORT bool StringToDouble(StringPiece input, double* output);
+BASE_EXPORT bool StringToDouble(StringPiece16 input, double* output);
+
+// Hex encoding ----------------------------------------------------------------
+
+// Returns a hex string representation of a binary buffer. The returned hex
+// string will be in upper case. This function does not check if |size| is
+// within reasonable limits since it's written with trusted data in mind.  If
+// you suspect that the data you want to format might be large, the absolute
+// max size for |size| should be is
+//   std::numeric_limits<size_t>::max() / 2
+BASE_EXPORT std::string HexEncode(const void* bytes, size_t size);
+BASE_EXPORT std::string HexEncode(base::span<const uint8_t> bytes);
+
+// Best effort conversion, see StringToInt above for restrictions.
+// Will only successful parse hex values that will fit into |output|, i.e.
+// -0x80000000 < |input| < 0x7FFFFFFF.
+BASE_EXPORT bool HexStringToInt(StringPiece input, int* output);
+
+// Best effort conversion, see StringToInt above for restrictions.
+// Will only successful parse hex values that will fit into |output|, i.e.
+// 0x00000000 < |input| < 0xFFFFFFFF.
+// The string is not required to start with 0x.
+BASE_EXPORT bool HexStringToUInt(StringPiece input, uint32_t* output);
+
+// Best effort conversion, see StringToInt above for restrictions.
+// Will only successful parse hex values that will fit into |output|, i.e.
+// -0x8000000000000000 < |input| < 0x7FFFFFFFFFFFFFFF.
+BASE_EXPORT bool HexStringToInt64(StringPiece input, int64_t* output);
+
+// Best effort conversion, see StringToInt above for restrictions.
+// Will only successful parse hex values that will fit into |output|, i.e.
+// 0x0000000000000000 < |input| < 0xFFFFFFFFFFFFFFFF.
+// The string is not required to start with 0x.
+BASE_EXPORT bool HexStringToUInt64(StringPiece input, uint64_t* output);
+
+// Similar to the previous functions, except that output is a vector of bytes.
+// |*output| will contain as many bytes as were successfully parsed prior to the
+// error.  There is no overflow, but input.size() must be evenly divisible by 2.
+// Leading 0x or +/- are not allowed.
+BASE_EXPORT bool HexStringToBytes(StringPiece input,
+                                  std::vector<uint8_t>* output);
+
+// Same as HexStringToBytes, but for an std::string.
+BASE_EXPORT bool HexStringToString(StringPiece input, std::string* output);
+
+// Decodes the hex string |input| into a presized |output|. The output buffer
+// must be sized exactly to |input.size() / 2| or decoding will fail and no
+// bytes will be written to |output|. Decoding an empty input is also
+// considered a failure. When decoding fails due to encountering invalid input
+// characters, |output| will have been filled with the decoded bytes up until
+// the failure.
+BASE_EXPORT bool HexStringToSpan(StringPiece input, base::span<uint8_t> output);
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_
diff --git a/security/sandbox/chromium/base/strings/string_piece.cc b/security/sandbox/chromium/base/strings/string_piece.cc
new file mode 100644
index 0000000000..d743144a4e
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_piece.cc
@@ -0,0 +1,426 @@
+// 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.
+// Copied from strings/stringpiece.cc with modifications
+
+#include "base/strings/string_piece.h"
+
+#include <limits.h>
+
+#include <algorithm>
+#include <ostream>
+
+#include "base/logging.h"
+#include "base/strings/utf_string_conversions.h"
+
+namespace base {
+namespace {
+
+// For each character in characters_wanted, sets the index corresponding
+// to the ASCII code of that character to 1 in table.  This is used by
+// the find_.*_of methods below to tell whether or not a character is in
+// the lookup table in constant time.
+// The argument `table' must be an array that is large enough to hold all
+// the possible values of an unsigned char.  Thus it should be be declared
+// as follows:
+//   bool table[UCHAR_MAX + 1]
+inline void BuildLookupTable(const StringPiece& characters_wanted,
+                             bool* table) {
+  const size_t length = characters_wanted.length();
+  const char* const data = characters_wanted.data();
+  for (size_t i = 0; i < length; ++i) {
+    table[static_cast<unsigned char>(data[i])] = true;
+  }
+}
+
+}  // namespace
+
+// MSVC doesn't like complex extern templates and DLLs.
+#if !defined(COMPILER_MSVC)
+template class BasicStringPiece<std::string>;
+template class BasicStringPiece<string16>;
+#endif
+
+std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
+  o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
+  return o;
+}
+
+std::ostream& operator<<(std::ostream& o, const StringPiece16& piece) {
+  return o << UTF16ToUTF8(piece);
+}
+
+namespace internal {
+
+template<typename STR>
+void AppendToStringT(const BasicStringPiece<STR>& self, STR* target) {
+  if (!self.empty())
+    target->append(self.data(), self.size());
+}
+
+void AppendToString(const StringPiece& self, std::string* target) {
+  AppendToStringT(self, target);
+}
+
+void AppendToString(const StringPiece16& self, string16* target) {
+  AppendToStringT(self, target);
+}
+
+template<typename STR>
+size_t copyT(const BasicStringPiece<STR>& self,
+             typename STR::value_type* buf,
+             size_t n,
+             size_t pos) {
+  size_t ret = std::min(self.size() - pos, n);
+  memcpy(buf, self.data() + pos, ret * sizeof(typename STR::value_type));
+  return ret;
+}
+
+size_t copy(const StringPiece& self, char* buf, size_t n, size_t pos) {
+  return copyT(self, buf, n, pos);
+}
+
+size_t copy(const StringPiece16& self, char16* buf, size_t n, size_t pos) {
+  return copyT(self, buf, n, pos);
+}
+
+template<typename STR>
+size_t findT(const BasicStringPiece<STR>& self,
+             const BasicStringPiece<STR>& s,
+             size_t pos) {
+  if (pos > self.size())
+    return BasicStringPiece<STR>::npos;
+
+  typename BasicStringPiece<STR>::const_iterator result =
+      std::search(self.begin() + pos, self.end(), s.begin(), s.end());
+  const size_t xpos =
+    static_cast<size_t>(result - self.begin());
+  return xpos + s.size() <= self.size() ? xpos : BasicStringPiece<STR>::npos;
+}
+
+size_t find(const StringPiece& self, const StringPiece& s, size_t pos) {
+  return findT(self, s, pos);
+}
+
+size_t find(const StringPiece16& self, const StringPiece16& s, size_t pos) {
+  return findT(self, s, pos);
+}
+
+template<typename STR>
+size_t findT(const BasicStringPiece<STR>& self,
+             typename STR::value_type c,
+             size_t pos) {
+  if (pos >= self.size())
+    return BasicStringPiece<STR>::npos;
+
+  typename BasicStringPiece<STR>::const_iterator result =
+      std::find(self.begin() + pos, self.end(), c);
+  return result != self.end() ?
+      static_cast<size_t>(result - self.begin()) : BasicStringPiece<STR>::npos;
+}
+
+size_t find(const StringPiece& self, char c, size_t pos) {
+  return findT(self, c, pos);
+}
+
+size_t find(const StringPiece16& self, char16 c, size_t pos) {
+  return findT(self, c, pos);
+}
+
+template<typename STR>
+size_t rfindT(const BasicStringPiece<STR>& self,
+              const BasicStringPiece<STR>& s,
+              size_t pos) {
+  if (self.size() < s.size())
+    return BasicStringPiece<STR>::npos;
+
+  if (s.empty())
+    return std::min(self.size(), pos);
+
+  typename BasicStringPiece<STR>::const_iterator last =
+      self.begin() + std::min(self.size() - s.size(), pos) + s.size();
+  typename BasicStringPiece<STR>::const_iterator result =
+      std::find_end(self.begin(), last, s.begin(), s.end());
+  return result != last ?
+      static_cast<size_t>(result - self.begin()) : BasicStringPiece<STR>::npos;
+}
+
+size_t rfind(const StringPiece& self, const StringPiece& s, size_t pos) {
+  return rfindT(self, s, pos);
+}
+
+size_t rfind(const StringPiece16& self, const StringPiece16& s, size_t pos) {
+  return rfindT(self, s, pos);
+}
+
+template<typename STR>
+size_t rfindT(const BasicStringPiece<STR>& self,
+              typename STR::value_type c,
+              size_t pos) {
+  if (self.size() == 0)
+    return BasicStringPiece<STR>::npos;
+
+  for (size_t i = std::min(pos, self.size() - 1); ;
+       --i) {
+    if (self.data()[i] == c)
+      return i;
+    if (i == 0)
+      break;
+  }
+  return BasicStringPiece<STR>::npos;
+}
+
+size_t rfind(const StringPiece& self, char c, size_t pos) {
+  return rfindT(self, c, pos);
+}
+
+size_t rfind(const StringPiece16& self, char16 c, size_t pos) {
+  return rfindT(self, c, pos);
+}
+
+// 8-bit version using lookup table.
+size_t find_first_of(const StringPiece& self,
+                     const StringPiece& s,
+                     size_t pos) {
+  if (self.size() == 0 || s.size() == 0)
+    return StringPiece::npos;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.size() == 1)
+    return find(self, s.data()[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (size_t i = pos; i < self.size(); ++i) {
+    if (lookup[static_cast<unsigned char>(self.data()[i])]) {
+      return i;
+    }
+  }
+  return StringPiece::npos;
+}
+
+// 16-bit brute force version.
+size_t find_first_of(const StringPiece16& self,
+                     const StringPiece16& s,
+                     size_t pos) {
+  // Use the faster std::find() if searching for a single character.
+  StringPiece16::const_iterator found =
+      s.size() == 1 ? std::find(self.begin() + pos, self.end(), s[0])
+                    : std::find_first_of(self.begin() + pos, self.end(),
+                                         s.begin(), s.end());
+  if (found == self.end())
+    return StringPiece16::npos;
+  return found - self.begin();
+}
+
+// 8-bit version using lookup table.
+size_t find_first_not_of(const StringPiece& self,
+                         const StringPiece& s,
+                         size_t pos) {
+  if (self.size() == 0)
+    return StringPiece::npos;
+
+  if (s.size() == 0)
+    return 0;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.size() == 1)
+    return find_first_not_of(self, s.data()[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (size_t i = pos; i < self.size(); ++i) {
+    if (!lookup[static_cast<unsigned char>(self.data()[i])]) {
+      return i;
+    }
+  }
+  return StringPiece::npos;
+}
+
+// 16-bit brute-force version.
+BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
+                                     const StringPiece16& s,
+                                     size_t pos) {
+  if (self.size() == 0)
+    return StringPiece16::npos;
+
+  for (size_t self_i = pos; self_i < self.size(); ++self_i) {
+    bool found = false;
+    for (auto c : s) {
+      if (self[self_i] == c) {
+        found = true;
+        break;
+      }
+    }
+    if (!found)
+      return self_i;
+  }
+  return StringPiece16::npos;
+}
+
+template<typename STR>
+size_t find_first_not_ofT(const BasicStringPiece<STR>& self,
+                          typename STR::value_type c,
+                          size_t pos) {
+  if (self.size() == 0)
+    return BasicStringPiece<STR>::npos;
+
+  for (; pos < self.size(); ++pos) {
+    if (self.data()[pos] != c) {
+      return pos;
+    }
+  }
+  return BasicStringPiece<STR>::npos;
+}
+
+size_t find_first_not_of(const StringPiece& self,
+                         char c,
+                         size_t pos) {
+  return find_first_not_ofT(self, c, pos);
+}
+
+size_t find_first_not_of(const StringPiece16& self,
+                         char16 c,
+                         size_t pos) {
+  return find_first_not_ofT(self, c, pos);
+}
+
+// 8-bit version using lookup table.
+size_t find_last_of(const StringPiece& self, const StringPiece& s, size_t pos) {
+  if (self.size() == 0 || s.size() == 0)
+    return StringPiece::npos;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.size() == 1)
+    return rfind(self, s.data()[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (size_t i = std::min(pos, self.size() - 1); ; --i) {
+    if (lookup[static_cast<unsigned char>(self.data()[i])])
+      return i;
+    if (i == 0)
+      break;
+  }
+  return StringPiece::npos;
+}
+
+// 16-bit brute-force version.
+size_t find_last_of(const StringPiece16& self,
+                    const StringPiece16& s,
+                    size_t pos) {
+  if (self.size() == 0)
+    return StringPiece16::npos;
+
+  for (size_t self_i = std::min(pos, self.size() - 1); ;
+       --self_i) {
+    for (auto c : s) {
+      if (self.data()[self_i] == c)
+        return self_i;
+    }
+    if (self_i == 0)
+      break;
+  }
+  return StringPiece16::npos;
+}
+
+// 8-bit version using lookup table.
+size_t find_last_not_of(const StringPiece& self,
+                        const StringPiece& s,
+                        size_t pos) {
+  if (self.size() == 0)
+    return StringPiece::npos;
+
+  size_t i = std::min(pos, self.size() - 1);
+  if (s.size() == 0)
+    return i;
+
+  // Avoid the cost of BuildLookupTable() for a single-character search.
+  if (s.size() == 1)
+    return find_last_not_of(self, s.data()[0], pos);
+
+  bool lookup[UCHAR_MAX + 1] = { false };
+  BuildLookupTable(s, lookup);
+  for (; ; --i) {
+    if (!lookup[static_cast<unsigned char>(self.data()[i])])
+      return i;
+    if (i == 0)
+      break;
+  }
+  return StringPiece::npos;
+}
+
+// 16-bit brute-force version.
+size_t find_last_not_of(const StringPiece16& self,
+                        const StringPiece16& s,
+                        size_t pos) {
+  if (self.size() == 0)
+    return StringPiece::npos;
+
+  for (size_t self_i = std::min(pos, self.size() - 1); ; --self_i) {
+    bool found = false;
+    for (auto c : s) {
+      if (self.data()[self_i] == c) {
+        found = true;
+        break;
+      }
+    }
+    if (!found)
+      return self_i;
+    if (self_i == 0)
+      break;
+  }
+  return StringPiece16::npos;
+}
+
+template<typename STR>
+size_t find_last_not_ofT(const BasicStringPiece<STR>& self,
+                         typename STR::value_type c,
+                         size_t pos) {
+  if (self.size() == 0)
+    return BasicStringPiece<STR>::npos;
+
+  for (size_t i = std::min(pos, self.size() - 1); ; --i) {
+    if (self.data()[i] != c)
+      return i;
+    if (i == 0)
+      break;
+  }
+  return BasicStringPiece<STR>::npos;
+}
+
+size_t find_last_not_of(const StringPiece& self,
+                        char c,
+                        size_t pos) {
+  return find_last_not_ofT(self, c, pos);
+}
+
+size_t find_last_not_of(const StringPiece16& self,
+                        char16 c,
+                        size_t pos) {
+  return find_last_not_ofT(self, c, pos);
+}
+
+template<typename STR>
+BasicStringPiece<STR> substrT(const BasicStringPiece<STR>& self,
+                              size_t pos,
+                              size_t n) {
+  if (pos > self.size()) pos = self.size();
+  if (n > self.size() - pos) n = self.size() - pos;
+  return BasicStringPiece<STR>(self.data() + pos, n);
+}
+
+StringPiece substr(const StringPiece& self,
+                   size_t pos,
+                   size_t n) {
+  return substrT(self, pos, n);
+}
+
+StringPiece16 substr(const StringPiece16& self,
+                     size_t pos,
+                     size_t n) {
+  return substrT(self, pos, n);
+}
+
+}  // namespace internal
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/string_piece.h b/security/sandbox/chromium/base/strings/string_piece.h
new file mode 100644
index 0000000000..536bf3f023
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_piece.h
@@ -0,0 +1,513 @@
+// 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.
+// Copied from strings/stringpiece.h with modifications
+//
+// A string-like object that points to a sized piece of memory.
+//
+// You can use StringPiece as a function or method parameter.  A StringPiece
+// parameter can receive a double-quoted string literal argument, a "const
+// char*" argument, a string argument, or a StringPiece argument with no data
+// copying.  Systematic use of StringPiece for arguments reduces data
+// copies and strlen() calls.
+//
+// Prefer passing StringPieces by value:
+//   void MyFunction(StringPiece arg);
+// If circumstances require, you may also pass by const reference:
+//   void MyFunction(const StringPiece& arg);  // not preferred
+// Both of these have the same lifetime semantics.  Passing by value
+// generates slightly smaller code.  For more discussion, Googlers can see
+// the thread go/stringpiecebyvalue on c-users.
+
+#ifndef BASE_STRINGS_STRING_PIECE_H_
+#define BASE_STRINGS_STRING_PIECE_H_
+
+#include <stddef.h>
+
+#include <iosfwd>
+#include <string>
+#include <type_traits>
+
+#include "base/base_export.h"
+#include "base/logging.h"
+#include "base/strings/char_traits.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_piece_forward.h"
+
+namespace base {
+
+// internal --------------------------------------------------------------------
+
+// Many of the StringPiece functions use different implementations for the
+// 8-bit and 16-bit versions, and we don't want lots of template expansions in
+// this (very common) header that will slow down compilation.
+//
+// So here we define overloaded functions called by the StringPiece template.
+// For those that share an implementation, the two versions will expand to a
+// template internal to the .cc file.
+namespace internal {
+
+BASE_EXPORT void AppendToString(const StringPiece& self, std::string* target);
+BASE_EXPORT void AppendToString(const StringPiece16& self, string16* target);
+
+BASE_EXPORT size_t copy(const StringPiece& self,
+                        char* buf,
+                        size_t n,
+                        size_t pos);
+BASE_EXPORT size_t copy(const StringPiece16& self,
+                        char16* buf,
+                        size_t n,
+                        size_t pos);
+
+BASE_EXPORT size_t find(const StringPiece& self,
+                        const StringPiece& s,
+                        size_t pos);
+BASE_EXPORT size_t find(const StringPiece16& self,
+                        const StringPiece16& s,
+                        size_t pos);
+BASE_EXPORT size_t find(const StringPiece& self,
+                        char c,
+                        size_t pos);
+BASE_EXPORT size_t find(const StringPiece16& self,
+                        char16 c,
+                        size_t pos);
+
+BASE_EXPORT size_t rfind(const StringPiece& self,
+                         const StringPiece& s,
+                         size_t pos);
+BASE_EXPORT size_t rfind(const StringPiece16& self,
+                         const StringPiece16& s,
+                         size_t pos);
+BASE_EXPORT size_t rfind(const StringPiece& self,
+                         char c,
+                         size_t pos);
+BASE_EXPORT size_t rfind(const StringPiece16& self,
+                         char16 c,
+                         size_t pos);
+
+BASE_EXPORT size_t find_first_of(const StringPiece& self,
+                                 const StringPiece& s,
+                                 size_t pos);
+BASE_EXPORT size_t find_first_of(const StringPiece16& self,
+                                 const StringPiece16& s,
+                                 size_t pos);
+
+BASE_EXPORT size_t find_first_not_of(const StringPiece& self,
+                                     const StringPiece& s,
+                                     size_t pos);
+BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
+                                     const StringPiece16& s,
+                                     size_t pos);
+BASE_EXPORT size_t find_first_not_of(const StringPiece& self,
+                                     char c,
+                                     size_t pos);
+BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
+                                     char16 c,
+                                     size_t pos);
+
+BASE_EXPORT size_t find_last_of(const StringPiece& self,
+                                const StringPiece& s,
+                                size_t pos);
+BASE_EXPORT size_t find_last_of(const StringPiece16& self,
+                                const StringPiece16& s,
+                                size_t pos);
+BASE_EXPORT size_t find_last_of(const StringPiece& self,
+                                char c,
+                                size_t pos);
+BASE_EXPORT size_t find_last_of(const StringPiece16& self,
+                                char16 c,
+                                size_t pos);
+
+BASE_EXPORT size_t find_last_not_of(const StringPiece& self,
+                                    const StringPiece& s,
+                                    size_t pos);
+BASE_EXPORT size_t find_last_not_of(const StringPiece16& self,
+                                    const StringPiece16& s,
+                                    size_t pos);
+BASE_EXPORT size_t find_last_not_of(const StringPiece16& self,
+                                    char16 c,
+                                    size_t pos);
+BASE_EXPORT size_t find_last_not_of(const StringPiece& self,
+                                    char c,
+                                    size_t pos);
+
+BASE_EXPORT StringPiece substr(const StringPiece& self,
+                               size_t pos,
+                               size_t n);
+BASE_EXPORT StringPiece16 substr(const StringPiece16& self,
+                                 size_t pos,
+                                 size_t n);
+
+}  // namespace internal
+
+// BasicStringPiece ------------------------------------------------------------
+
+// Defines the types, methods, operators, and data members common to both
+// StringPiece and StringPiece16.
+//
+// This is templatized by string class type rather than character type, so
+// BasicStringPiece<std::string> or BasicStringPiece<base::string16>.
+template <typename STRING_TYPE> class BasicStringPiece {
+ public:
+  // Standard STL container boilerplate.
+  typedef size_t size_type;
+  typedef typename STRING_TYPE::value_type value_type;
+  typedef const value_type* pointer;
+  typedef const value_type& reference;
+  typedef const value_type& const_reference;
+  typedef ptrdiff_t difference_type;
+  typedef const value_type* const_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+  static const size_type npos;
+
+ public:
+  // We provide non-explicit singleton constructors so users can pass
+  // in a "const char*" or a "string" wherever a "StringPiece" is
+  // expected (likewise for char16, string16, StringPiece16).
+  constexpr BasicStringPiece() : ptr_(NULL), length_(0) {}
+  // TODO(dcheng): Construction from nullptr is not allowed for
+  // std::basic_string_view, so remove the special handling for it.
+  // Note: This doesn't just use STRING_TYPE::traits_type::length(), since that
+  // isn't constexpr until C++17.
+  constexpr BasicStringPiece(const value_type* str)
+      : ptr_(str), length_(!str ? 0 : CharTraits<value_type>::length(str)) {}
+  BasicStringPiece(const STRING_TYPE& str)
+      : ptr_(str.data()), length_(str.size()) {}
+  constexpr BasicStringPiece(const value_type* offset, size_type len)
+      : ptr_(offset), length_(len) {}
+  BasicStringPiece(const typename STRING_TYPE::const_iterator& begin,
+                   const typename STRING_TYPE::const_iterator& end) {
+    DCHECK(begin <= end) << "StringPiece iterators swapped or invalid.";
+    length_ = static_cast<size_t>(std::distance(begin, end));
+
+    // The length test before assignment is to avoid dereferencing an iterator
+    // that may point to the end() of a string.
+    ptr_ = length_ > 0 ? &*begin : nullptr;
+  }
+
+  // data() may return a pointer to a buffer with embedded NULs, and the
+  // returned buffer may or may not be null terminated.  Therefore it is
+  // typically a mistake to pass data() to a routine that expects a NUL
+  // terminated string.
+  constexpr const value_type* data() const { return ptr_; }
+  constexpr size_type size() const noexcept { return length_; }
+  constexpr size_type length() const noexcept { return length_; }
+  bool empty() const { return length_ == 0; }
+
+  constexpr value_type operator[](size_type i) const {
+    CHECK(i < length_);
+    return ptr_[i];
+  }
+
+  value_type front() const {
+    CHECK_NE(0UL, length_);
+    return ptr_[0];
+  }
+
+  value_type back() const {
+    CHECK_NE(0UL, length_);
+    return ptr_[length_ - 1];
+  }
+
+  constexpr void remove_prefix(size_type n) {
+    CHECK(n <= length_);
+    ptr_ += n;
+    length_ -= n;
+  }
+
+  constexpr void remove_suffix(size_type n) {
+    CHECK(n <= length_);
+    length_ -= n;
+  }
+
+  constexpr int compare(BasicStringPiece x) const noexcept {
+    int r = CharTraits<value_type>::compare(
+        ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_));
+    if (r == 0) {
+      if (length_ < x.length_) r = -1;
+      else if (length_ > x.length_) r = +1;
+    }
+    return r;
+  }
+
+  // This is the style of conversion preferred by std::string_view in C++17.
+  explicit operator STRING_TYPE() const { return as_string(); }
+
+  STRING_TYPE as_string() const {
+    // std::string doesn't like to take a NULL pointer even with a 0 size.
+    return empty() ? STRING_TYPE() : STRING_TYPE(data(), size());
+  }
+
+  const_iterator begin() const { return ptr_; }
+  const_iterator end() const { return ptr_ + length_; }
+  const_reverse_iterator rbegin() const {
+    return const_reverse_iterator(ptr_ + length_);
+  }
+  const_reverse_iterator rend() const {
+    return const_reverse_iterator(ptr_);
+  }
+
+  size_type max_size() const { return length_; }
+  size_type capacity() const { return length_; }
+
+  void AppendToString(STRING_TYPE* target) const {
+    internal::AppendToString(*this, target);
+  }
+
+  size_type copy(value_type* buf, size_type n, size_type pos = 0) const {
+    return internal::copy(*this, buf, n, pos);
+  }
+
+  // Does "this" start with "x"
+  constexpr bool starts_with(BasicStringPiece x) const noexcept {
+    return (
+        (this->length_ >= x.length_) &&
+        (CharTraits<value_type>::compare(this->ptr_, x.ptr_, x.length_) == 0));
+  }
+
+  // Does "this" end with "x"
+  constexpr bool ends_with(BasicStringPiece x) const noexcept {
+    return ((this->length_ >= x.length_) &&
+            (CharTraits<value_type>::compare(
+                 this->ptr_ + (this->length_ - x.length_), x.ptr_, x.length_) ==
+             0));
+  }
+
+  // find: Search for a character or substring at a given offset.
+  size_type find(const BasicStringPiece<STRING_TYPE>& s,
+                 size_type pos = 0) const {
+    return internal::find(*this, s, pos);
+  }
+  size_type find(value_type c, size_type pos = 0) const {
+    return internal::find(*this, c, pos);
+  }
+
+  // rfind: Reverse find.
+  size_type rfind(const BasicStringPiece& s,
+                  size_type pos = BasicStringPiece::npos) const {
+    return internal::rfind(*this, s, pos);
+  }
+  size_type rfind(value_type c, size_type pos = BasicStringPiece::npos) const {
+    return internal::rfind(*this, c, pos);
+  }
+
+  // find_first_of: Find the first occurence of one of a set of characters.
+  size_type find_first_of(const BasicStringPiece& s,
+                          size_type pos = 0) const {
+    return internal::find_first_of(*this, s, pos);
+  }
+  size_type find_first_of(value_type c, size_type pos = 0) const {
+    return find(c, pos);
+  }
+
+  // find_first_not_of: Find the first occurence not of a set of characters.
+  size_type find_first_not_of(const BasicStringPiece& s,
+                              size_type pos = 0) const {
+    return internal::find_first_not_of(*this, s, pos);
+  }
+  size_type find_first_not_of(value_type c, size_type pos = 0) const {
+    return internal::find_first_not_of(*this, c, pos);
+  }
+
+  // find_last_of: Find the last occurence of one of a set of characters.
+  size_type find_last_of(const BasicStringPiece& s,
+                         size_type pos = BasicStringPiece::npos) const {
+    return internal::find_last_of(*this, s, pos);
+  }
+  size_type find_last_of(value_type c,
+                         size_type pos = BasicStringPiece::npos) const {
+    return rfind(c, pos);
+  }
+
+  // find_last_not_of: Find the last occurence not of a set of characters.
+  size_type find_last_not_of(const BasicStringPiece& s,
+                             size_type pos = BasicStringPiece::npos) const {
+    return internal::find_last_not_of(*this, s, pos);
+  }
+  size_type find_last_not_of(value_type c,
+                             size_type pos = BasicStringPiece::npos) const {
+    return internal::find_last_not_of(*this, c, pos);
+  }
+
+  // substr.
+  BasicStringPiece substr(size_type pos,
+                          size_type n = BasicStringPiece::npos) const {
+    return internal::substr(*this, pos, n);
+  }
+
+ protected:
+  const value_type* ptr_;
+  size_type length_;
+};
+
+template <typename STRING_TYPE>
+const typename BasicStringPiece<STRING_TYPE>::size_type
+BasicStringPiece<STRING_TYPE>::npos =
+    typename BasicStringPiece<STRING_TYPE>::size_type(-1);
+
+// MSVC doesn't like complex extern templates and DLLs.
+#if !defined(COMPILER_MSVC)
+extern template class BASE_EXPORT BasicStringPiece<std::string>;
+extern template class BASE_EXPORT BasicStringPiece<string16>;
+#endif
+
+// Comparison operators --------------------------------------------------------
+// operator ==
+template <typename StringT>
+constexpr bool operator==(BasicStringPiece<StringT> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return lhs.size() == rhs.size() && lhs.compare(rhs) == 0;
+}
+
+// Here and below we make use of std::common_type_t to emulate an identity type
+// transformation. This creates a non-deduced context, so that we can compare
+// StringPieces with types that implicitly convert to StringPieces. See
+// https://wg21.link/n3766 for details.
+// Furthermore, we require dummy template parameters for these overloads to work
+// around a name mangling issue on Windows.
+template <typename StringT, int = 1>
+constexpr bool operator==(
+    BasicStringPiece<StringT> lhs,
+    std::common_type_t<BasicStringPiece<StringT>> rhs) noexcept {
+  return lhs.size() == rhs.size() && lhs.compare(rhs) == 0;
+}
+
+template <typename StringT, int = 2>
+constexpr bool operator==(std::common_type_t<BasicStringPiece<StringT>> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return lhs.size() == rhs.size() && lhs.compare(rhs) == 0;
+}
+
+// operator !=
+template <typename StringT>
+constexpr bool operator!=(BasicStringPiece<StringT> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return !(lhs == rhs);
+}
+
+template <typename StringT, int = 1>
+constexpr bool operator!=(
+    BasicStringPiece<StringT> lhs,
+    std::common_type_t<BasicStringPiece<StringT>> rhs) noexcept {
+  return !(lhs == rhs);
+}
+
+template <typename StringT, int = 2>
+constexpr bool operator!=(std::common_type_t<BasicStringPiece<StringT>> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return !(lhs == rhs);
+}
+
+// operator <
+template <typename StringT>
+constexpr bool operator<(BasicStringPiece<StringT> lhs,
+                         BasicStringPiece<StringT> rhs) noexcept {
+  return lhs.compare(rhs) < 0;
+}
+
+template <typename StringT, int = 1>
+constexpr bool operator<(
+    BasicStringPiece<StringT> lhs,
+    std::common_type_t<BasicStringPiece<StringT>> rhs) noexcept {
+  return lhs.compare(rhs) < 0;
+}
+
+template <typename StringT, int = 2>
+constexpr bool operator<(std::common_type_t<BasicStringPiece<StringT>> lhs,
+                         BasicStringPiece<StringT> rhs) noexcept {
+  return lhs.compare(rhs) < 0;
+}
+
+// operator >
+template <typename StringT>
+constexpr bool operator>(BasicStringPiece<StringT> lhs,
+                         BasicStringPiece<StringT> rhs) noexcept {
+  return rhs < lhs;
+}
+
+template <typename StringT, int = 1>
+constexpr bool operator>(
+    BasicStringPiece<StringT> lhs,
+    std::common_type_t<BasicStringPiece<StringT>> rhs) noexcept {
+  return rhs < lhs;
+}
+
+template <typename StringT, int = 2>
+constexpr bool operator>(std::common_type_t<BasicStringPiece<StringT>> lhs,
+                         BasicStringPiece<StringT> rhs) noexcept {
+  return rhs < lhs;
+}
+
+// operator <=
+template <typename StringT>
+constexpr bool operator<=(BasicStringPiece<StringT> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return !(rhs < lhs);
+}
+
+template <typename StringT, int = 1>
+constexpr bool operator<=(
+    BasicStringPiece<StringT> lhs,
+    std::common_type_t<BasicStringPiece<StringT>> rhs) noexcept {
+  return !(rhs < lhs);
+}
+
+template <typename StringT, int = 2>
+constexpr bool operator<=(std::common_type_t<BasicStringPiece<StringT>> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return !(rhs < lhs);
+}
+
+// operator >=
+template <typename StringT>
+constexpr bool operator>=(BasicStringPiece<StringT> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return !(lhs < rhs);
+}
+
+template <typename StringT, int = 1>
+constexpr bool operator>=(
+    BasicStringPiece<StringT> lhs,
+    std::common_type_t<BasicStringPiece<StringT>> rhs) noexcept {
+  return !(lhs < rhs);
+}
+
+template <typename StringT, int = 2>
+constexpr bool operator>=(std::common_type_t<BasicStringPiece<StringT>> lhs,
+                          BasicStringPiece<StringT> rhs) noexcept {
+  return !(lhs < rhs);
+}
+
+BASE_EXPORT std::ostream& operator<<(std::ostream& o,
+                                     const StringPiece& piece);
+
+BASE_EXPORT std::ostream& operator<<(std::ostream& o,
+                                     const StringPiece16& piece);
+
+// Hashing ---------------------------------------------------------------------
+
+// We provide appropriate hash functions so StringPiece and StringPiece16 can
+// be used as keys in hash sets and maps.
+
+// This hash function is copied from base/strings/string16.h. We don't use the
+// ones already defined for string and string16 directly because it would
+// require the string constructors to be called, which we don't want.
+
+template <typename StringPieceType>
+struct StringPieceHashImpl {
+  std::size_t operator()(StringPieceType sp) const {
+    std::size_t result = 0;
+    for (auto c : sp)
+      result = (result * 131) + c;
+    return result;
+  }
+};
+
+using StringPieceHash = StringPieceHashImpl<StringPiece>;
+using StringPiece16Hash = StringPieceHashImpl<StringPiece16>;
+using WStringPieceHash = StringPieceHashImpl<WStringPiece>;
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRING_PIECE_H_
diff --git a/security/sandbox/chromium/base/strings/string_piece_forward.h b/security/sandbox/chromium/base/strings/string_piece_forward.h
new file mode 100644
index 0000000000..b50b9806c9
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_piece_forward.h
@@ -0,0 +1,24 @@
+// Copyright 2017 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.
+
+// Forward declaration of StringPiece types from base/strings/string_piece.h
+
+#ifndef BASE_STRINGS_STRING_PIECE_FORWARD_H_
+#define BASE_STRINGS_STRING_PIECE_FORWARD_H_
+
+#include <string>
+
+#include "base/strings/string16.h"
+
+namespace base {
+
+template <typename STRING_TYPE>
+class BasicStringPiece;
+typedef BasicStringPiece<std::string> StringPiece;
+typedef BasicStringPiece<string16> StringPiece16;
+typedef BasicStringPiece<std::wstring> WStringPiece;
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRING_PIECE_FORWARD_H_
diff --git a/security/sandbox/chromium/base/strings/string_split.cc b/security/sandbox/chromium/base/strings/string_split.cc
new file mode 100644
index 0000000000..42bc5e5b60
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_split.cc
@@ -0,0 +1,254 @@
+// 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/strings/string_split.h"
+
+#include <stddef.h>
+
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "base/third_party/icu/icu_utf.h"
+
+namespace base {
+
+namespace {
+
+// Returns either the ASCII or UTF-16 whitespace.
+template<typename Str> BasicStringPiece<Str> WhitespaceForType();
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+template <>
+WStringPiece WhitespaceForType<std::wstring>() {
+  return kWhitespaceWide;
+}
+#endif
+
+template<> StringPiece16 WhitespaceForType<string16>() {
+  return kWhitespaceUTF16;
+}
+template<> StringPiece WhitespaceForType<std::string>() {
+  return kWhitespaceASCII;
+}
+
+// General string splitter template. Can take 8- or 16-bit input, can produce
+// the corresponding string or StringPiece output.
+template <typename OutputStringType, typename Str>
+static std::vector<OutputStringType> SplitStringT(
+    BasicStringPiece<Str> str,
+    BasicStringPiece<Str> delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) {
+  std::vector<OutputStringType> result;
+  if (str.empty())
+    return result;
+
+  size_t start = 0;
+  while (start != Str::npos) {
+    size_t end = str.find_first_of(delimiter, start);
+
+    BasicStringPiece<Str> piece;
+    if (end == Str::npos) {
+      piece = str.substr(start);
+      start = Str::npos;
+    } else {
+      piece = str.substr(start, end - start);
+      start = end + 1;
+    }
+
+    if (whitespace == TRIM_WHITESPACE)
+      piece = TrimString(piece, WhitespaceForType<Str>(), TRIM_ALL);
+
+    if (result_type == SPLIT_WANT_ALL || !piece.empty())
+      result.emplace_back(piece);
+  }
+  return result;
+}
+
+bool AppendStringKeyValue(StringPiece input,
+                          char delimiter,
+                          StringPairs* result) {
+  // Always append a new item regardless of success (it might be empty). The
+  // below code will copy the strings directly into the result pair.
+  result->resize(result->size() + 1);
+  auto& result_pair = result->back();
+
+  // Find the delimiter.
+  size_t end_key_pos = input.find_first_of(delimiter);
+  if (end_key_pos == std::string::npos) {
+    DVLOG(1) << "cannot find delimiter in: " << input;
+    return false;    // No delimiter.
+  }
+  result_pair.first = std::string(input.substr(0, end_key_pos));
+
+  // Find the value string.
+  StringPiece remains = input.substr(end_key_pos, input.size() - end_key_pos);
+  size_t begin_value_pos = remains.find_first_not_of(delimiter);
+  if (begin_value_pos == StringPiece::npos) {
+    DVLOG(1) << "cannot parse value from input: " << input;
+    return false;   // No value.
+  }
+
+  result_pair.second = std::string(
+      remains.substr(begin_value_pos, remains.size() - begin_value_pos));
+
+  return true;
+}
+
+template <typename OutputStringType, typename Str>
+std::vector<OutputStringType> SplitStringUsingSubstrT(
+    BasicStringPiece<Str> input,
+    BasicStringPiece<Str> delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) {
+  using Piece = BasicStringPiece<Str>;
+  using size_type = typename Piece::size_type;
+
+  std::vector<OutputStringType> result;
+  for (size_type begin_index = 0, end_index = 0; end_index != Piece::npos;
+       begin_index = end_index + delimiter.size()) {
+    end_index = input.find(delimiter, begin_index);
+    Piece term = end_index == Piece::npos
+                     ? input.substr(begin_index)
+                     : input.substr(begin_index, end_index - begin_index);
+
+    if (whitespace == TRIM_WHITESPACE)
+      term = TrimString(term, WhitespaceForType<Str>(), TRIM_ALL);
+
+    if (result_type == SPLIT_WANT_ALL || !term.empty())
+      result.emplace_back(term);
+  }
+
+  return result;
+}
+
+}  // namespace
+
+std::vector<std::string> SplitString(StringPiece input,
+                                     StringPiece separators,
+                                     WhitespaceHandling whitespace,
+                                     SplitResult result_type) {
+  return SplitStringT<std::string>(input, separators, whitespace, result_type);
+}
+
+std::vector<string16> SplitString(StringPiece16 input,
+                                  StringPiece16 separators,
+                                  WhitespaceHandling whitespace,
+                                  SplitResult result_type) {
+  return SplitStringT<string16>(input, separators, whitespace, result_type);
+}
+
+std::vector<StringPiece> SplitStringPiece(StringPiece input,
+                                          StringPiece separators,
+                                          WhitespaceHandling whitespace,
+                                          SplitResult result_type) {
+  return SplitStringT<StringPiece>(input, separators, whitespace, result_type);
+}
+
+std::vector<StringPiece16> SplitStringPiece(StringPiece16 input,
+                                            StringPiece16 separators,
+                                            WhitespaceHandling whitespace,
+                                            SplitResult result_type) {
+  return SplitStringT<StringPiece16>(input, separators, whitespace,
+                                     result_type);
+}
+
+bool SplitStringIntoKeyValuePairs(StringPiece input,
+                                  char key_value_delimiter,
+                                  char key_value_pair_delimiter,
+                                  StringPairs* key_value_pairs) {
+  return SplitStringIntoKeyValuePairsUsingSubstr(
+      input, key_value_delimiter, StringPiece(&key_value_pair_delimiter, 1),
+      key_value_pairs);
+}
+
+bool SplitStringIntoKeyValuePairsUsingSubstr(
+    StringPiece input,
+    char key_value_delimiter,
+    StringPiece key_value_pair_delimiter,
+    StringPairs* key_value_pairs) {
+  key_value_pairs->clear();
+
+  std::vector<StringPiece> pairs = SplitStringPieceUsingSubstr(
+      input, key_value_pair_delimiter, TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY);
+  key_value_pairs->reserve(pairs.size());
+
+  bool success = true;
+  for (const StringPiece& pair : pairs) {
+    if (!AppendStringKeyValue(pair, key_value_delimiter, key_value_pairs)) {
+      // Don't return here, to allow for pairs without associated
+      // value or key; just record that the split failed.
+      success = false;
+    }
+  }
+  return success;
+}
+
+std::vector<string16> SplitStringUsingSubstr(StringPiece16 input,
+                                             StringPiece16 delimiter,
+                                             WhitespaceHandling whitespace,
+                                             SplitResult result_type) {
+  return SplitStringUsingSubstrT<string16>(input, delimiter, whitespace,
+                                           result_type);
+}
+
+std::vector<std::string> SplitStringUsingSubstr(StringPiece input,
+                                                StringPiece delimiter,
+                                                WhitespaceHandling whitespace,
+                                                SplitResult result_type) {
+  return SplitStringUsingSubstrT<std::string>(input, delimiter, whitespace,
+                                              result_type);
+}
+
+std::vector<StringPiece16> SplitStringPieceUsingSubstr(
+    StringPiece16 input,
+    StringPiece16 delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) {
+  std::vector<StringPiece16> result;
+  return SplitStringUsingSubstrT<StringPiece16>(input, delimiter, whitespace,
+                                                result_type);
+}
+
+std::vector<StringPiece> SplitStringPieceUsingSubstr(
+    StringPiece input,
+    StringPiece delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) {
+  return SplitStringUsingSubstrT<StringPiece>(input, delimiter, whitespace,
+                                              result_type);
+}
+
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+std::vector<std::wstring> SplitString(WStringPiece input,
+                                      WStringPiece separators,
+                                      WhitespaceHandling whitespace,
+                                      SplitResult result_type) {
+  return SplitStringT<std::wstring>(input, separators, whitespace, result_type);
+}
+
+std::vector<WStringPiece> SplitStringPiece(WStringPiece input,
+                                           WStringPiece separators,
+                                           WhitespaceHandling whitespace,
+                                           SplitResult result_type) {
+  return SplitStringT<WStringPiece>(input, separators, whitespace, result_type);
+}
+
+std::vector<std::wstring> SplitStringUsingSubstr(WStringPiece input,
+                                                 WStringPiece delimiter,
+                                                 WhitespaceHandling whitespace,
+                                                 SplitResult result_type) {
+  return SplitStringUsingSubstrT<std::wstring>(input, delimiter, whitespace,
+                                               result_type);
+}
+
+std::vector<WStringPiece> SplitStringPieceUsingSubstr(
+    WStringPiece input,
+    WStringPiece delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) {
+  return SplitStringUsingSubstrT<WStringPiece>(input, delimiter, whitespace,
+                                               result_type);
+}
+#endif
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/string_split.h b/security/sandbox/chromium/base/strings/string_split.h
new file mode 100644
index 0000000000..efa8b199fe
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_split.h
@@ -0,0 +1,169 @@
+// 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.
+
+#ifndef BASE_STRINGS_STRING_SPLIT_H_
+#define BASE_STRINGS_STRING_SPLIT_H_
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
+#include "build/build_config.h"
+
+namespace base {
+
+enum WhitespaceHandling {
+  KEEP_WHITESPACE,
+  TRIM_WHITESPACE,
+};
+
+enum SplitResult {
+  // Strictly return all results.
+  //
+  // If the input is ",," and the separator is ',' this will return a
+  // vector of three empty strings.
+  SPLIT_WANT_ALL,
+
+  // Only nonempty results will be added to the results. Multiple separators
+  // will be coalesced. Separators at the beginning and end of the input will
+  // be ignored. With TRIM_WHITESPACE, whitespace-only results will be dropped.
+  //
+  // If the input is ",," and the separator is ',', this will return an empty
+  // vector.
+  SPLIT_WANT_NONEMPTY,
+};
+
+// Split the given string on ANY of the given separators, returning copies of
+// the result.
+//
+// Note this is inverse of JoinString() defined in string_util.h.
+//
+// To split on either commas or semicolons, keeping all whitespace:
+//
+//   std::vector<std::string> tokens = base::SplitString(
+//       input, ", WARN_UNUSED_RESULT;", base::KEEP_WHITESPACE,
+//       base::SPLIT_WANT_ALL) WARN_UNUSED_RESULT;
+BASE_EXPORT std::vector<std::string> SplitString(StringPiece input,
+                                                 StringPiece separators,
+                                                 WhitespaceHandling whitespace,
+                                                 SplitResult result_type)
+    WARN_UNUSED_RESULT;
+BASE_EXPORT std::vector<string16> SplitString(StringPiece16 input,
+                                              StringPiece16 separators,
+                                              WhitespaceHandling whitespace,
+                                              SplitResult result_type)
+    WARN_UNUSED_RESULT;
+
+// Like SplitString above except it returns a vector of StringPieces which
+// reference the original buffer without copying. Although you have to be
+// careful to keep the original string unmodified, this provides an efficient
+// way to iterate through tokens in a string.
+//
+// Note this is inverse of JoinString() defined in string_util.h.
+//
+// To iterate through all whitespace-separated tokens in an input string:
+//
+//   for (const auto& cur :
+//        base::SplitStringPiece(input, base::kWhitespaceASCII,
+//                               base::KEEP_WHITESPACE,
+//                               base::SPLIT_WANT_NONEMPTY)) {
+//     ...
+BASE_EXPORT std::vector<StringPiece> SplitStringPiece(
+    StringPiece input,
+    StringPiece separators,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+BASE_EXPORT std::vector<StringPiece16> SplitStringPiece(
+    StringPiece16 input,
+    StringPiece16 separators,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+
+using StringPairs = std::vector<std::pair<std::string, std::string>>;
+
+// Splits |line| into key value pairs according to the given delimiters and
+// removes whitespace leading each key and trailing each value. Returns true
+// only if each pair has a non-empty key and value. |key_value_pairs| will
+// include ("","") pairs for entries without |key_value_delimiter|.
+BASE_EXPORT bool SplitStringIntoKeyValuePairs(StringPiece input,
+                                              char key_value_delimiter,
+                                              char key_value_pair_delimiter,
+                                              StringPairs* key_value_pairs);
+
+// Similar to SplitStringIntoKeyValuePairs, but use a substring
+// |key_value_pair_delimiter| instead of a single char.
+BASE_EXPORT bool SplitStringIntoKeyValuePairsUsingSubstr(
+    StringPiece input,
+    char key_value_delimiter,
+    StringPiece key_value_pair_delimiter,
+    StringPairs* key_value_pairs);
+
+// Similar to SplitString, but use a substring delimiter instead of a list of
+// characters that are all possible delimiters.
+BASE_EXPORT std::vector<string16> SplitStringUsingSubstr(
+    StringPiece16 input,
+    StringPiece16 delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+BASE_EXPORT std::vector<std::string> SplitStringUsingSubstr(
+    StringPiece input,
+    StringPiece delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+
+// Like SplitStringUsingSubstr above except it returns a vector of StringPieces
+// which reference the original buffer without copying. Although you have to be
+// careful to keep the original string unmodified, this provides an efficient
+// way to iterate through tokens in a string.
+//
+// To iterate through all newline-separated tokens in an input string:
+//
+//   for (const auto& cur :
+//        base::SplitStringUsingSubstr(input, "\r\n",
+//                                     base::KEEP_WHITESPACE,
+//                                     base::SPLIT_WANT_NONEMPTY)) {
+//     ...
+BASE_EXPORT std::vector<StringPiece16> SplitStringPieceUsingSubstr(
+    StringPiece16 input,
+    StringPiece16 delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+BASE_EXPORT std::vector<StringPiece> SplitStringPieceUsingSubstr(
+    StringPiece input,
+    StringPiece delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+BASE_EXPORT std::vector<std::wstring> SplitString(WStringPiece input,
+                                                  WStringPiece separators,
+                                                  WhitespaceHandling whitespace,
+                                                  SplitResult result_type)
+    WARN_UNUSED_RESULT;
+
+BASE_EXPORT std::vector<WStringPiece> SplitStringPiece(
+    WStringPiece input,
+    WStringPiece separators,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+
+BASE_EXPORT std::vector<std::wstring> SplitStringUsingSubstr(
+    WStringPiece input,
+    WStringPiece delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+
+BASE_EXPORT std::vector<WStringPiece> SplitStringPieceUsingSubstr(
+    WStringPiece input,
+    WStringPiece delimiter,
+    WhitespaceHandling whitespace,
+    SplitResult result_type) WARN_UNUSED_RESULT;
+#endif
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRING_SPLIT_H_
diff --git a/security/sandbox/chromium/base/strings/string_util.cc b/security/sandbox/chromium/base/strings/string_util.cc
new file mode 100644
index 0000000000..7e140fae48
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_util.cc
@@ -0,0 +1,1157 @@
+// 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.
+
+#include "base/strings/string_util.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <math.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include <algorithm>
+#include <limits>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/no_destructor.h"
+#include "base/stl_util.h"
+#include "base/strings/utf_string_conversion_utils.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/third_party/icu/icu_utf.h"
+#include "build/build_config.h"
+
+namespace base {
+
+namespace {
+
+// Used by ReplaceStringPlaceholders to track the position in the string of
+// replaced parameters.
+struct ReplacementOffset {
+  ReplacementOffset(uintptr_t parameter, size_t offset)
+      : parameter(parameter),
+        offset(offset) {}
+
+  // Index of the parameter.
+  uintptr_t parameter;
+
+  // Starting position in the string.
+  size_t offset;
+};
+
+static bool CompareParameter(const ReplacementOffset& elem1,
+                             const ReplacementOffset& elem2) {
+  return elem1.parameter < elem2.parameter;
+}
+
+// Overloaded function to append one string onto the end of another. Having a
+// separate overload for |source| as both string and StringPiece allows for more
+// efficient usage from functions templated to work with either type (avoiding a
+// redundant call to the BasicStringPiece constructor in both cases).
+template <typename string_type>
+inline void AppendToString(string_type* target, const string_type& source) {
+  target->append(source);
+}
+
+template <typename string_type>
+inline void AppendToString(string_type* target,
+                           const BasicStringPiece<string_type>& source) {
+  source.AppendToString(target);
+}
+
+// Assuming that a pointer is the size of a "machine word", then
+// uintptr_t is an integer type that is also a machine word.
+using MachineWord = uintptr_t;
+
+inline bool IsMachineWordAligned(const void* pointer) {
+  return !(reinterpret_cast<MachineWord>(pointer) & (sizeof(MachineWord) - 1));
+}
+
+template <typename CharacterType>
+struct NonASCIIMask;
+template <>
+struct NonASCIIMask<char> {
+  static constexpr MachineWord value() {
+    return static_cast<MachineWord>(0x8080808080808080ULL);
+  }
+};
+template <>
+struct NonASCIIMask<char16> {
+  static constexpr MachineWord value() {
+    return static_cast<MachineWord>(0xFF80FF80FF80FF80ULL);
+  }
+};
+#if defined(WCHAR_T_IS_UTF32)
+template <>
+struct NonASCIIMask<wchar_t> {
+  static constexpr MachineWord value() {
+    return static_cast<MachineWord>(0xFFFFFF80FFFFFF80ULL);
+  }
+};
+#endif  // WCHAR_T_IS_UTF32
+
+}  // namespace
+
+bool IsWprintfFormatPortable(const wchar_t* format) {
+  for (const wchar_t* position = format; *position != '\0'; ++position) {
+    if (*position == '%') {
+      bool in_specification = true;
+      bool modifier_l = false;
+      while (in_specification) {
+        // Eat up characters until reaching a known specifier.
+        if (*++position == '\0') {
+          // The format string ended in the middle of a specification.  Call
+          // it portable because no unportable specifications were found.  The
+          // string is equally broken on all platforms.
+          return true;
+        }
+
+        if (*position == 'l') {
+          // 'l' is the only thing that can save the 's' and 'c' specifiers.
+          modifier_l = true;
+        } else if (((*position == 's' || *position == 'c') && !modifier_l) ||
+                   *position == 'S' || *position == 'C' || *position == 'F' ||
+                   *position == 'D' || *position == 'O' || *position == 'U') {
+          // Not portable.
+          return false;
+        }
+
+        if (wcschr(L"diouxXeEfgGaAcspn%", *position)) {
+          // Portable, keep scanning the rest of the format string.
+          in_specification = false;
+        }
+      }
+    }
+  }
+
+  return true;
+}
+
+namespace {
+
+template<typename StringType>
+StringType ToLowerASCIIImpl(BasicStringPiece<StringType> str) {
+  StringType ret;
+  ret.reserve(str.size());
+  for (size_t i = 0; i < str.size(); i++)
+    ret.push_back(ToLowerASCII(str[i]));
+  return ret;
+}
+
+template<typename StringType>
+StringType ToUpperASCIIImpl(BasicStringPiece<StringType> str) {
+  StringType ret;
+  ret.reserve(str.size());
+  for (size_t i = 0; i < str.size(); i++)
+    ret.push_back(ToUpperASCII(str[i]));
+  return ret;
+}
+
+}  // namespace
+
+std::string ToLowerASCII(StringPiece str) {
+  return ToLowerASCIIImpl<std::string>(str);
+}
+
+string16 ToLowerASCII(StringPiece16 str) {
+  return ToLowerASCIIImpl<string16>(str);
+}
+
+std::string ToUpperASCII(StringPiece str) {
+  return ToUpperASCIIImpl<std::string>(str);
+}
+
+string16 ToUpperASCII(StringPiece16 str) {
+  return ToUpperASCIIImpl<string16>(str);
+}
+
+template<class StringType>
+int CompareCaseInsensitiveASCIIT(BasicStringPiece<StringType> a,
+                                 BasicStringPiece<StringType> b) {
+  // Find the first characters that aren't equal and compare them.  If the end
+  // of one of the strings is found before a nonequal character, the lengths
+  // of the strings are compared.
+  size_t i = 0;
+  while (i < a.length() && i < b.length()) {
+    typename StringType::value_type lower_a = ToLowerASCII(a[i]);
+    typename StringType::value_type lower_b = ToLowerASCII(b[i]);
+    if (lower_a < lower_b)
+      return -1;
+    if (lower_a > lower_b)
+      return 1;
+    i++;
+  }
+
+  // End of one string hit before finding a different character. Expect the
+  // common case to be "strings equal" at this point so check that first.
+  if (a.length() == b.length())
+    return 0;
+
+  if (a.length() < b.length())
+    return -1;
+  return 1;
+}
+
+int CompareCaseInsensitiveASCII(StringPiece a, StringPiece b) {
+  return CompareCaseInsensitiveASCIIT<std::string>(a, b);
+}
+
+int CompareCaseInsensitiveASCII(StringPiece16 a, StringPiece16 b) {
+  return CompareCaseInsensitiveASCIIT<string16>(a, b);
+}
+
+bool EqualsCaseInsensitiveASCII(StringPiece a, StringPiece b) {
+  if (a.length() != b.length())
+    return false;
+  return CompareCaseInsensitiveASCIIT<std::string>(a, b) == 0;
+}
+
+bool EqualsCaseInsensitiveASCII(StringPiece16 a, StringPiece16 b) {
+  if (a.length() != b.length())
+    return false;
+  return CompareCaseInsensitiveASCIIT<string16>(a, b) == 0;
+}
+
+const std::string& EmptyString() {
+  static const base::NoDestructor<std::string> s;
+  return *s;
+}
+
+const string16& EmptyString16() {
+  static const base::NoDestructor<string16> s16;
+  return *s16;
+}
+
+template <class StringType>
+bool ReplaceCharsT(const StringType& input,
+                   BasicStringPiece<StringType> find_any_of_these,
+                   BasicStringPiece<StringType> replace_with,
+                   StringType* output);
+
+bool ReplaceChars(const string16& input,
+                  StringPiece16 replace_chars,
+                  StringPiece16 replace_with,
+                  string16* output) {
+  return ReplaceCharsT(input, replace_chars, replace_with, output);
+}
+
+bool ReplaceChars(const std::string& input,
+                  StringPiece replace_chars,
+                  StringPiece replace_with,
+                  std::string* output) {
+  return ReplaceCharsT(input, replace_chars, replace_with, output);
+}
+
+bool RemoveChars(const string16& input,
+                 StringPiece16 remove_chars,
+                 string16* output) {
+  return ReplaceCharsT(input, remove_chars, StringPiece16(), output);
+}
+
+bool RemoveChars(const std::string& input,
+                 StringPiece remove_chars,
+                 std::string* output) {
+  return ReplaceCharsT(input, remove_chars, StringPiece(), output);
+}
+
+template <typename Str>
+TrimPositions TrimStringT(BasicStringPiece<Str> input,
+                          BasicStringPiece<Str> trim_chars,
+                          TrimPositions positions,
+                          Str* output) {
+  // Find the edges of leading/trailing whitespace as desired. Need to use
+  // a StringPiece version of input to be able to call find* on it with the
+  // StringPiece version of trim_chars (normally the trim_chars will be a
+  // constant so avoid making a copy).
+  const size_t last_char = input.length() - 1;
+  const size_t first_good_char =
+      (positions & TRIM_LEADING) ? input.find_first_not_of(trim_chars) : 0;
+  const size_t last_good_char = (positions & TRIM_TRAILING)
+                                    ? input.find_last_not_of(trim_chars)
+                                    : last_char;
+
+  // When the string was all trimmed, report that we stripped off characters
+  // from whichever position the caller was interested in. For empty input, we
+  // stripped no characters, but we still need to clear |output|.
+  if (input.empty() || first_good_char == Str::npos ||
+      last_good_char == Str::npos) {
+    bool input_was_empty = input.empty();  // in case output == &input
+    output->clear();
+    return input_was_empty ? TRIM_NONE : positions;
+  }
+
+  // Trim.
+  output->assign(input.data() + first_good_char,
+                 last_good_char - first_good_char + 1);
+
+  // Return where we trimmed from.
+  return static_cast<TrimPositions>(
+      (first_good_char == 0 ? TRIM_NONE : TRIM_LEADING) |
+      (last_good_char == last_char ? TRIM_NONE : TRIM_TRAILING));
+}
+
+bool TrimString(StringPiece16 input,
+                StringPiece16 trim_chars,
+                string16* output) {
+  return TrimStringT(input, trim_chars, TRIM_ALL, output) != TRIM_NONE;
+}
+
+bool TrimString(StringPiece input,
+                StringPiece trim_chars,
+                std::string* output) {
+  return TrimStringT(input, trim_chars, TRIM_ALL, output) != TRIM_NONE;
+}
+
+template<typename Str>
+BasicStringPiece<Str> TrimStringPieceT(BasicStringPiece<Str> input,
+                                       BasicStringPiece<Str> trim_chars,
+                                       TrimPositions positions) {
+  size_t begin = (positions & TRIM_LEADING) ?
+      input.find_first_not_of(trim_chars) : 0;
+  size_t end = (positions & TRIM_TRAILING) ?
+      input.find_last_not_of(trim_chars) + 1 : input.size();
+  return input.substr(begin, end - begin);
+}
+
+StringPiece16 TrimString(StringPiece16 input,
+                         StringPiece16 trim_chars,
+                         TrimPositions positions) {
+  return TrimStringPieceT(input, trim_chars, positions);
+}
+
+StringPiece TrimString(StringPiece input,
+                       StringPiece trim_chars,
+                       TrimPositions positions) {
+  return TrimStringPieceT(input, trim_chars, positions);
+}
+
+void TruncateUTF8ToByteSize(const std::string& input,
+                            const size_t byte_size,
+                            std::string* output) {
+  DCHECK(output);
+  if (byte_size > input.length()) {
+    *output = input;
+    return;
+  }
+  DCHECK_LE(byte_size,
+            static_cast<uint32_t>(std::numeric_limits<int32_t>::max()));
+  // Note: This cast is necessary because CBU8_NEXT uses int32_ts.
+  int32_t truncation_length = static_cast<int32_t>(byte_size);
+  int32_t char_index = truncation_length - 1;
+  const char* data = input.data();
+
+  // Using CBU8, we will move backwards from the truncation point
+  // to the beginning of the string looking for a valid UTF8
+  // character.  Once a full UTF8 character is found, we will
+  // truncate the string to the end of that character.
+  while (char_index >= 0) {
+    int32_t prev = char_index;
+    base_icu::UChar32 code_point = 0;
+    CBU8_NEXT(data, char_index, truncation_length, code_point);
+    if (!IsValidCharacter(code_point) ||
+        !IsValidCodepoint(code_point)) {
+      char_index = prev - 1;
+    } else {
+      break;
+    }
+  }
+
+  if (char_index >= 0 )
+    *output = input.substr(0, char_index);
+  else
+    output->clear();
+}
+
+TrimPositions TrimWhitespace(StringPiece16 input,
+                             TrimPositions positions,
+                             string16* output) {
+  return TrimStringT(input, StringPiece16(kWhitespaceUTF16), positions, output);
+}
+
+StringPiece16 TrimWhitespace(StringPiece16 input,
+                             TrimPositions positions) {
+  return TrimStringPieceT(input, StringPiece16(kWhitespaceUTF16), positions);
+}
+
+TrimPositions TrimWhitespaceASCII(StringPiece input,
+                                  TrimPositions positions,
+                                  std::string* output) {
+  return TrimStringT(input, StringPiece(kWhitespaceASCII), positions, output);
+}
+
+StringPiece TrimWhitespaceASCII(StringPiece input, TrimPositions positions) {
+  return TrimStringPieceT(input, StringPiece(kWhitespaceASCII), positions);
+}
+
+template<typename STR>
+STR CollapseWhitespaceT(const STR& text,
+                        bool trim_sequences_with_line_breaks) {
+  STR result;
+  result.resize(text.size());
+
+  // Set flags to pretend we're already in a trimmed whitespace sequence, so we
+  // will trim any leading whitespace.
+  bool in_whitespace = true;
+  bool already_trimmed = true;
+
+  int chars_written = 0;
+  for (typename STR::const_iterator i(text.begin()); i != text.end(); ++i) {
+    if (IsUnicodeWhitespace(*i)) {
+      if (!in_whitespace) {
+        // Reduce all whitespace sequences to a single space.
+        in_whitespace = true;
+        result[chars_written++] = L' ';
+      }
+      if (trim_sequences_with_line_breaks && !already_trimmed &&
+          ((*i == '\n') || (*i == '\r'))) {
+        // Whitespace sequences containing CR or LF are eliminated entirely.
+        already_trimmed = true;
+        --chars_written;
+      }
+    } else {
+      // Non-whitespace chracters are copied straight across.
+      in_whitespace = false;
+      already_trimmed = false;
+      result[chars_written++] = *i;
+    }
+  }
+
+  if (in_whitespace && !already_trimmed) {
+    // Any trailing whitespace is eliminated.
+    --chars_written;
+  }
+
+  result.resize(chars_written);
+  return result;
+}
+
+string16 CollapseWhitespace(const string16& text,
+                            bool trim_sequences_with_line_breaks) {
+  return CollapseWhitespaceT(text, trim_sequences_with_line_breaks);
+}
+
+std::string CollapseWhitespaceASCII(const std::string& text,
+                                    bool trim_sequences_with_line_breaks) {
+  return CollapseWhitespaceT(text, trim_sequences_with_line_breaks);
+}
+
+bool ContainsOnlyChars(StringPiece input, StringPiece characters) {
+  return input.find_first_not_of(characters) == StringPiece::npos;
+}
+
+bool ContainsOnlyChars(StringPiece16 input, StringPiece16 characters) {
+  return input.find_first_not_of(characters) == StringPiece16::npos;
+}
+
+template <class Char>
+inline bool DoIsStringASCII(const Char* characters, size_t length) {
+  if (!length)
+    return true;
+  constexpr MachineWord non_ascii_bit_mask = NonASCIIMask<Char>::value();
+  MachineWord all_char_bits = 0;
+  const Char* end = characters + length;
+
+  // Prologue: align the input.
+  while (!IsMachineWordAligned(characters) && characters < end)
+    all_char_bits |= *characters++;
+  if (all_char_bits & non_ascii_bit_mask)
+    return false;
+
+  // Compare the values of CPU word size.
+  constexpr size_t chars_per_word = sizeof(MachineWord) / sizeof(Char);
+  constexpr int batch_count = 16;
+  while (characters <= end - batch_count * chars_per_word) {
+    all_char_bits = 0;
+    for (int i = 0; i < batch_count; ++i) {
+      all_char_bits |= *(reinterpret_cast<const MachineWord*>(characters));
+      characters += chars_per_word;
+    }
+    if (all_char_bits & non_ascii_bit_mask)
+      return false;
+  }
+
+  // Process the remaining words.
+  all_char_bits = 0;
+  while (characters <= end - chars_per_word) {
+    all_char_bits |= *(reinterpret_cast<const MachineWord*>(characters));
+    characters += chars_per_word;
+  }
+
+  // Process the remaining bytes.
+  while (characters < end)
+    all_char_bits |= *characters++;
+
+  return !(all_char_bits & non_ascii_bit_mask);
+}
+
+bool IsStringASCII(StringPiece str) {
+  return DoIsStringASCII(str.data(), str.length());
+}
+
+bool IsStringASCII(StringPiece16 str) {
+  return DoIsStringASCII(str.data(), str.length());
+}
+
+#if defined(WCHAR_T_IS_UTF32)
+bool IsStringASCII(WStringPiece str) {
+  return DoIsStringASCII(str.data(), str.length());
+}
+#endif
+
+template <bool (*Validator)(uint32_t)>
+inline static bool DoIsStringUTF8(StringPiece str) {
+  const char* src = str.data();
+  int32_t src_len = static_cast<int32_t>(str.length());
+  int32_t char_index = 0;
+
+  while (char_index < src_len) {
+    int32_t code_point;
+    CBU8_NEXT(src, char_index, src_len, code_point);
+    if (!Validator(code_point))
+      return false;
+  }
+  return true;
+}
+
+bool IsStringUTF8(StringPiece str) {
+  return DoIsStringUTF8<IsValidCharacter>(str);
+}
+
+bool IsStringUTF8AllowingNoncharacters(StringPiece str) {
+  return DoIsStringUTF8<IsValidCodepoint>(str);
+}
+
+// Implementation note: Normally this function will be called with a hardcoded
+// constant for the lowercase_ascii parameter. Constructing a StringPiece from
+// a C constant requires running strlen, so the result will be two passes
+// through the buffers, one to file the length of lowercase_ascii, and one to
+// compare each letter.
+//
+// This function could have taken a const char* to avoid this and only do one
+// pass through the string. But the strlen is faster than the case-insensitive
+// compares and lets us early-exit in the case that the strings are different
+// lengths (will often be the case for non-matches). So whether one approach or
+// the other will be faster depends on the case.
+//
+// The hardcoded strings are typically very short so it doesn't matter, and the
+// string piece gives additional flexibility for the caller (doesn't have to be
+// null terminated) so we choose the StringPiece route.
+template<typename Str>
+static inline bool DoLowerCaseEqualsASCII(BasicStringPiece<Str> str,
+                                          StringPiece lowercase_ascii) {
+  if (str.size() != lowercase_ascii.size())
+    return false;
+  for (size_t i = 0; i < str.size(); i++) {
+    if (ToLowerASCII(str[i]) != lowercase_ascii[i])
+      return false;
+  }
+  return true;
+}
+
+bool LowerCaseEqualsASCII(StringPiece str, StringPiece lowercase_ascii) {
+  return DoLowerCaseEqualsASCII<std::string>(str, lowercase_ascii);
+}
+
+bool LowerCaseEqualsASCII(StringPiece16 str, StringPiece lowercase_ascii) {
+  return DoLowerCaseEqualsASCII<string16>(str, lowercase_ascii);
+}
+
+bool EqualsASCII(StringPiece16 str, StringPiece ascii) {
+  if (str.length() != ascii.length())
+    return false;
+  return std::equal(ascii.begin(), ascii.end(), str.begin());
+}
+
+template<typename Str>
+bool StartsWithT(BasicStringPiece<Str> str,
+                 BasicStringPiece<Str> search_for,
+                 CompareCase case_sensitivity) {
+  if (search_for.size() > str.size())
+    return false;
+
+  BasicStringPiece<Str> source = str.substr(0, search_for.size());
+
+  switch (case_sensitivity) {
+    case CompareCase::SENSITIVE:
+      return source == search_for;
+
+    case CompareCase::INSENSITIVE_ASCII:
+      return std::equal(
+          search_for.begin(), search_for.end(),
+          source.begin(),
+          CaseInsensitiveCompareASCII<typename Str::value_type>());
+
+    default:
+      NOTREACHED();
+      return false;
+  }
+}
+
+bool StartsWith(StringPiece str,
+                StringPiece search_for,
+                CompareCase case_sensitivity) {
+  return StartsWithT<std::string>(str, search_for, case_sensitivity);
+}
+
+bool StartsWith(StringPiece16 str,
+                StringPiece16 search_for,
+                CompareCase case_sensitivity) {
+  return StartsWithT<string16>(str, search_for, case_sensitivity);
+}
+
+template <typename Str>
+bool EndsWithT(BasicStringPiece<Str> str,
+               BasicStringPiece<Str> search_for,
+               CompareCase case_sensitivity) {
+  if (search_for.size() > str.size())
+    return false;
+
+  BasicStringPiece<Str> source = str.substr(str.size() - search_for.size(),
+                                            search_for.size());
+
+  switch (case_sensitivity) {
+    case CompareCase::SENSITIVE:
+      return source == search_for;
+
+    case CompareCase::INSENSITIVE_ASCII:
+      return std::equal(
+          source.begin(), source.end(),
+          search_for.begin(),
+          CaseInsensitiveCompareASCII<typename Str::value_type>());
+
+    default:
+      NOTREACHED();
+      return false;
+  }
+}
+
+bool EndsWith(StringPiece str,
+              StringPiece search_for,
+              CompareCase case_sensitivity) {
+  return EndsWithT<std::string>(str, search_for, case_sensitivity);
+}
+
+bool EndsWith(StringPiece16 str,
+              StringPiece16 search_for,
+              CompareCase case_sensitivity) {
+  return EndsWithT<string16>(str, search_for, case_sensitivity);
+}
+
+char HexDigitToInt(wchar_t c) {
+  DCHECK(IsHexDigit(c));
+  if (c >= '0' && c <= '9')
+    return static_cast<char>(c - '0');
+  if (c >= 'A' && c <= 'F')
+    return static_cast<char>(c - 'A' + 10);
+  if (c >= 'a' && c <= 'f')
+    return static_cast<char>(c - 'a' + 10);
+  return 0;
+}
+
+bool IsUnicodeWhitespace(wchar_t c) {
+  // kWhitespaceWide is a NULL-terminated string
+  for (const wchar_t* cur = kWhitespaceWide; *cur; ++cur) {
+    if (*cur == c)
+      return true;
+  }
+  return false;
+}
+
+static const char* const kByteStringsUnlocalized[] = {
+  " B",
+  " kB",
+  " MB",
+  " GB",
+  " TB",
+  " PB"
+};
+
+string16 FormatBytesUnlocalized(int64_t bytes) {
+  double unit_amount = static_cast<double>(bytes);
+  size_t dimension = 0;
+  const int kKilo = 1024;
+  while (unit_amount >= kKilo &&
+         dimension < base::size(kByteStringsUnlocalized) - 1) {
+    unit_amount /= kKilo;
+    dimension++;
+  }
+
+  char buf[64];
+  if (bytes != 0 && dimension > 0 && unit_amount < 100) {
+    base::snprintf(buf, base::size(buf), "%.1lf%s", unit_amount,
+                   kByteStringsUnlocalized[dimension]);
+  } else {
+    base::snprintf(buf, base::size(buf), "%.0lf%s", unit_amount,
+                   kByteStringsUnlocalized[dimension]);
+  }
+
+  return ASCIIToUTF16(buf);
+}
+
+// A Matcher for DoReplaceMatchesAfterOffset() that matches substrings.
+template <class StringType>
+struct SubstringMatcher {
+  BasicStringPiece<StringType> find_this;
+
+  size_t Find(const StringType& input, size_t pos) {
+    return input.find(find_this.data(), pos, find_this.length());
+  }
+  size_t MatchSize() { return find_this.length(); }
+};
+
+// A Matcher for DoReplaceMatchesAfterOffset() that matches single characters.
+template <class StringType>
+struct CharacterMatcher {
+  BasicStringPiece<StringType> find_any_of_these;
+
+  size_t Find(const StringType& input, size_t pos) {
+    return input.find_first_of(find_any_of_these.data(), pos,
+                               find_any_of_these.length());
+  }
+  constexpr size_t MatchSize() { return 1; }
+};
+
+enum class ReplaceType { REPLACE_ALL, REPLACE_FIRST };
+
+// Runs in O(n) time in the length of |str|, and transforms the string without
+// reallocating when possible. Returns |true| if any matches were found.
+//
+// This is parameterized on a |Matcher| traits type, so that it can be the
+// implementation for both ReplaceChars() and ReplaceSubstringsAfterOffset().
+template <class StringType, class Matcher>
+bool DoReplaceMatchesAfterOffset(StringType* str,
+                                 size_t initial_offset,
+                                 Matcher matcher,
+                                 BasicStringPiece<StringType> replace_with,
+                                 ReplaceType replace_type) {
+  using CharTraits = typename StringType::traits_type;
+
+  const size_t find_length = matcher.MatchSize();
+  if (!find_length)
+    return false;
+
+  // If the find string doesn't appear, there's nothing to do.
+  size_t first_match = matcher.Find(*str, initial_offset);
+  if (first_match == StringType::npos)
+    return false;
+
+  // If we're only replacing one instance, there's no need to do anything
+  // complicated.
+  const size_t replace_length = replace_with.length();
+  if (replace_type == ReplaceType::REPLACE_FIRST) {
+    str->replace(first_match, find_length, replace_with.data(), replace_length);
+    return true;
+  }
+
+  // If the find and replace strings are the same length, we can simply use
+  // replace() on each instance, and finish the entire operation in O(n) time.
+  if (find_length == replace_length) {
+    auto* buffer = &((*str)[0]);
+    for (size_t offset = first_match; offset != StringType::npos;
+         offset = matcher.Find(*str, offset + replace_length)) {
+      CharTraits::copy(buffer + offset, replace_with.data(), replace_length);
+    }
+    return true;
+  }
+
+  // Since the find and replace strings aren't the same length, a loop like the
+  // one above would be O(n^2) in the worst case, as replace() will shift the
+  // entire remaining string each time. We need to be more clever to keep things
+  // O(n).
+  //
+  // When the string is being shortened, it's possible to just shift the matches
+  // down in one pass while finding, and truncate the length at the end of the
+  // search.
+  //
+  // If the string is being lengthened, more work is required. The strategy used
+  // here is to make two find() passes through the string. The first pass counts
+  // the number of matches to determine the new size. The second pass will
+  // either construct the new string into a new buffer (if the existing buffer
+  // lacked capacity), or else -- if there is room -- create a region of scratch
+  // space after |first_match| by shifting the tail of the string to a higher
+  // index, and doing in-place moves from the tail to lower indices thereafter.
+  size_t str_length = str->length();
+  size_t expansion = 0;
+  if (replace_length > find_length) {
+    // This operation lengthens the string; determine the new length by counting
+    // matches.
+    const size_t expansion_per_match = (replace_length - find_length);
+    size_t num_matches = 0;
+    for (size_t match = first_match; match != StringType::npos;
+         match = matcher.Find(*str, match + find_length)) {
+      expansion += expansion_per_match;
+      ++num_matches;
+    }
+    const size_t final_length = str_length + expansion;
+
+    if (str->capacity() < final_length) {
+      // If we'd have to allocate a new buffer to grow the string, build the
+      // result directly into the new allocation via append().
+      StringType src(str->get_allocator());
+      str->swap(src);
+      str->reserve(final_length);
+
+      size_t pos = 0;
+      for (size_t match = first_match;; match = matcher.Find(src, pos)) {
+        str->append(src, pos, match - pos);
+        str->append(replace_with.data(), replace_length);
+        pos = match + find_length;
+
+        // A mid-loop test/break enables skipping the final Find() call; the
+        // number of matches is known, so don't search past the last one.
+        if (!--num_matches)
+          break;
+      }
+
+      // Handle substring after the final match.
+      str->append(src, pos, str_length - pos);
+      return true;
+    }
+
+    // Prepare for the copy/move loop below -- expand the string to its final
+    // size by shifting the data after the first match to the end of the resized
+    // string.
+    size_t shift_src = first_match + find_length;
+    size_t shift_dst = shift_src + expansion;
+
+    // Big |expansion| factors (relative to |str_length|) require padding up to
+    // |shift_dst|.
+    if (shift_dst > str_length)
+      str->resize(shift_dst);
+
+    str->replace(shift_dst, str_length - shift_src, *str, shift_src,
+                 str_length - shift_src);
+    str_length = final_length;
+  }
+
+  // We can alternate replacement and move operations. This won't overwrite the
+  // unsearched region of the string so long as |write_offset| <= |read_offset|;
+  // that condition is always satisfied because:
+  //
+  //   (a) If the string is being shortened, |expansion| is zero and
+  //       |write_offset| grows slower than |read_offset|.
+  //
+  //   (b) If the string is being lengthened, |write_offset| grows faster than
+  //       |read_offset|, but |expansion| is big enough so that |write_offset|
+  //       will only catch up to |read_offset| at the point of the last match.
+  auto* buffer = &((*str)[0]);
+  size_t write_offset = first_match;
+  size_t read_offset = first_match + expansion;
+  do {
+    if (replace_length) {
+      CharTraits::copy(buffer + write_offset, replace_with.data(),
+                       replace_length);
+      write_offset += replace_length;
+    }
+    read_offset += find_length;
+
+    // min() clamps StringType::npos (the largest unsigned value) to str_length.
+    size_t match = std::min(matcher.Find(*str, read_offset), str_length);
+
+    size_t length = match - read_offset;
+    if (length) {
+      CharTraits::move(buffer + write_offset, buffer + read_offset, length);
+      write_offset += length;
+      read_offset += length;
+    }
+  } while (read_offset < str_length);
+
+  // If we're shortening the string, truncate it now.
+  str->resize(write_offset);
+  return true;
+}
+
+template <class StringType>
+bool ReplaceCharsT(const StringType& input,
+                   BasicStringPiece<StringType> find_any_of_these,
+                   BasicStringPiece<StringType> replace_with,
+                   StringType* output) {
+  // Commonly, this is called with output and input being the same string; in
+  // that case, this assignment is inexpensive.
+  *output = input;
+
+  return DoReplaceMatchesAfterOffset(
+      output, 0, CharacterMatcher<StringType>{find_any_of_these}, replace_with,
+      ReplaceType::REPLACE_ALL);
+}
+
+void ReplaceFirstSubstringAfterOffset(string16* str,
+                                      size_t start_offset,
+                                      StringPiece16 find_this,
+                                      StringPiece16 replace_with) {
+  DoReplaceMatchesAfterOffset(str, start_offset,
+                              SubstringMatcher<string16>{find_this},
+                              replace_with, ReplaceType::REPLACE_FIRST);
+}
+
+void ReplaceFirstSubstringAfterOffset(std::string* str,
+                                      size_t start_offset,
+                                      StringPiece find_this,
+                                      StringPiece replace_with) {
+  DoReplaceMatchesAfterOffset(str, start_offset,
+                              SubstringMatcher<std::string>{find_this},
+                              replace_with, ReplaceType::REPLACE_FIRST);
+}
+
+void ReplaceSubstringsAfterOffset(string16* str,
+                                  size_t start_offset,
+                                  StringPiece16 find_this,
+                                  StringPiece16 replace_with) {
+  DoReplaceMatchesAfterOffset(str, start_offset,
+                              SubstringMatcher<string16>{find_this},
+                              replace_with, ReplaceType::REPLACE_ALL);
+}
+
+void ReplaceSubstringsAfterOffset(std::string* str,
+                                  size_t start_offset,
+                                  StringPiece find_this,
+                                  StringPiece replace_with) {
+  DoReplaceMatchesAfterOffset(str, start_offset,
+                              SubstringMatcher<std::string>{find_this},
+                              replace_with, ReplaceType::REPLACE_ALL);
+}
+
+template <class string_type>
+inline typename string_type::value_type* WriteIntoT(string_type* str,
+                                                    size_t length_with_null) {
+  DCHECK_GE(length_with_null, 1u);
+  str->reserve(length_with_null);
+  str->resize(length_with_null - 1);
+  return &((*str)[0]);
+}
+
+char* WriteInto(std::string* str, size_t length_with_null) {
+  return WriteIntoT(str, length_with_null);
+}
+
+char16* WriteInto(string16* str, size_t length_with_null) {
+  return WriteIntoT(str, length_with_null);
+}
+
+#if defined(_MSC_VER) && !defined(__clang__)
+// Work around VC++ code-gen bug. https://crbug.com/804884
+#pragma optimize("", off)
+#endif
+
+// Generic version for all JoinString overloads. |list_type| must be a sequence
+// (std::vector or std::initializer_list) of strings/StringPieces (std::string,
+// string16, StringPiece or StringPiece16). |string_type| is either std::string
+// or string16.
+template <typename list_type, typename string_type>
+static string_type JoinStringT(const list_type& parts,
+                               BasicStringPiece<string_type> sep) {
+  if (parts.size() == 0)
+    return string_type();
+
+  // Pre-allocate the eventual size of the string. Start with the size of all of
+  // the separators (note that this *assumes* parts.size() > 0).
+  size_t total_size = (parts.size() - 1) * sep.size();
+  for (const auto& part : parts)
+    total_size += part.size();
+  string_type result;
+  result.reserve(total_size);
+
+  auto iter = parts.begin();
+  DCHECK(iter != parts.end());
+  AppendToString(&result, *iter);
+  ++iter;
+
+  for (; iter != parts.end(); ++iter) {
+    sep.AppendToString(&result);
+    // Using the overloaded AppendToString allows this template function to work
+    // on both strings and StringPieces without creating an intermediate
+    // StringPiece object.
+    AppendToString(&result, *iter);
+  }
+
+  // Sanity-check that we pre-allocated correctly.
+  DCHECK_EQ(total_size, result.size());
+
+  return result;
+}
+
+std::string JoinString(const std::vector<std::string>& parts,
+                       StringPiece separator) {
+  return JoinStringT(parts, separator);
+}
+
+string16 JoinString(const std::vector<string16>& parts,
+                    StringPiece16 separator) {
+  return JoinStringT(parts, separator);
+}
+
+#if defined(_MSC_VER) && !defined(__clang__)
+// Work around VC++ code-gen bug. https://crbug.com/804884
+#pragma optimize("", on)
+#endif
+
+std::string JoinString(const std::vector<StringPiece>& parts,
+                       StringPiece separator) {
+  return JoinStringT(parts, separator);
+}
+
+string16 JoinString(const std::vector<StringPiece16>& parts,
+                    StringPiece16 separator) {
+  return JoinStringT(parts, separator);
+}
+
+std::string JoinString(std::initializer_list<StringPiece> parts,
+                       StringPiece separator) {
+  return JoinStringT(parts, separator);
+}
+
+string16 JoinString(std::initializer_list<StringPiece16> parts,
+                    StringPiece16 separator) {
+  return JoinStringT(parts, separator);
+}
+
+template<class FormatStringType, class OutStringType>
+OutStringType DoReplaceStringPlaceholders(
+    const FormatStringType& format_string,
+    const std::vector<OutStringType>& subst,
+    std::vector<size_t>* offsets) {
+  size_t substitutions = subst.size();
+  DCHECK_LT(substitutions, 10U);
+
+  size_t sub_length = 0;
+  for (const auto& cur : subst)
+    sub_length += cur.length();
+
+  OutStringType formatted;
+  formatted.reserve(format_string.length() + sub_length);
+
+  std::vector<ReplacementOffset> r_offsets;
+  for (auto i = format_string.begin(); i != format_string.end(); ++i) {
+    if ('$' == *i) {
+      if (i + 1 != format_string.end()) {
+        ++i;
+        if ('$' == *i) {
+          while (i != format_string.end() && '$' == *i) {
+            formatted.push_back('$');
+            ++i;
+          }
+          --i;
+        } else {
+          if (*i < '1' || *i > '9') {
+            DLOG(ERROR) << "Invalid placeholder: $" << *i;
+            continue;
+          }
+          uintptr_t index = *i - '1';
+          if (offsets) {
+            ReplacementOffset r_offset(index,
+                                       static_cast<int>(formatted.size()));
+            r_offsets.insert(
+                std::upper_bound(r_offsets.begin(), r_offsets.end(), r_offset,
+                                 &CompareParameter),
+                r_offset);
+          }
+          if (index < substitutions)
+            formatted.append(subst.at(index));
+        }
+      }
+    } else {
+      formatted.push_back(*i);
+    }
+  }
+  if (offsets) {
+    for (const auto& cur : r_offsets)
+      offsets->push_back(cur.offset);
+  }
+  return formatted;
+}
+
+string16 ReplaceStringPlaceholders(const string16& format_string,
+                                   const std::vector<string16>& subst,
+                                   std::vector<size_t>* offsets) {
+  return DoReplaceStringPlaceholders(format_string, subst, offsets);
+}
+
+std::string ReplaceStringPlaceholders(StringPiece format_string,
+                                      const std::vector<std::string>& subst,
+                                      std::vector<size_t>* offsets) {
+  return DoReplaceStringPlaceholders(format_string, subst, offsets);
+}
+
+string16 ReplaceStringPlaceholders(const string16& format_string,
+                                   const string16& a,
+                                   size_t* offset) {
+  std::vector<size_t> offsets;
+  std::vector<string16> subst;
+  subst.push_back(a);
+  string16 result = ReplaceStringPlaceholders(format_string, subst, &offsets);
+
+  DCHECK_EQ(1U, offsets.size());
+  if (offset)
+    *offset = offsets[0];
+  return result;
+}
+
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+
+TrimPositions TrimWhitespace(WStringPiece input,
+                             TrimPositions positions,
+                             std::wstring* output) {
+  return TrimStringT(input, WStringPiece(kWhitespaceWide), positions, output);
+}
+
+WStringPiece TrimWhitespace(WStringPiece input, TrimPositions positions) {
+  return TrimStringPieceT(input, WStringPiece(kWhitespaceWide), positions);
+}
+
+bool TrimString(WStringPiece input,
+                WStringPiece trim_chars,
+                std::wstring* output) {
+  return TrimStringT(input, trim_chars, TRIM_ALL, output) != TRIM_NONE;
+}
+
+WStringPiece TrimString(WStringPiece input,
+                        WStringPiece trim_chars,
+                        TrimPositions positions) {
+  return TrimStringPieceT(input, trim_chars, positions);
+}
+
+wchar_t* WriteInto(std::wstring* str, size_t length_with_null) {
+  return WriteIntoT(str, length_with_null);
+}
+
+#endif
+
+// The following code is compatible with the OpenBSD lcpy interface.  See:
+//   http://www.gratisoft.us/todd/papers/strlcpy.html
+//   ftp://ftp.openbsd.org/pub/OpenBSD/src/lib/libc/string/{wcs,str}lcpy.c
+
+namespace {
+
+template <typename CHAR>
+size_t lcpyT(CHAR* dst, const CHAR* src, size_t dst_size) {
+  for (size_t i = 0; i < dst_size; ++i) {
+    if ((dst[i] = src[i]) == 0)  // We hit and copied the terminating NULL.
+      return i;
+  }
+
+  // We were left off at dst_size.  We over copied 1 byte.  Null terminate.
+  if (dst_size != 0)
+    dst[dst_size - 1] = 0;
+
+  // Count the rest of the |src|, and return it's length in characters.
+  while (src[dst_size]) ++dst_size;
+  return dst_size;
+}
+
+}  // namespace
+
+size_t strlcpy(char* dst, const char* src, size_t dst_size) {
+  return lcpyT<char>(dst, src, dst_size);
+}
+size_t wcslcpy(wchar_t* dst, const wchar_t* src, size_t dst_size) {
+  return lcpyT<wchar_t>(dst, src, dst_size);
+}
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/string_util.h b/security/sandbox/chromium/base/strings/string_util.h
new file mode 100644
index 0000000000..f9f5e10ade
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_util.h
@@ -0,0 +1,568 @@
+// 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.
+//
+// This file defines utility functions for working with strings.
+
+#ifndef BASE_STRINGS_STRING_UTIL_H_
+#define BASE_STRINGS_STRING_UTIL_H_
+
+#include <ctype.h>
+#include <stdarg.h>   // va_list
+#include <stddef.h>
+#include <stdint.h>
+
+#include <initializer_list>
+#include <string>
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/stl_util.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"  // For implicit conversions.
+#include "build/build_config.h"
+
+namespace base {
+
+// C standard-library functions that aren't cross-platform are provided as
+// "base::...", and their prototypes are listed below. These functions are
+// then implemented as inline calls to the platform-specific equivalents in the
+// platform-specific headers.
+
+// Wrapper for vsnprintf that always null-terminates and always returns the
+// number of characters that would be in an untruncated formatted
+// string, even when truncation occurs.
+int vsnprintf(char* buffer, size_t size, const char* format, va_list arguments)
+    PRINTF_FORMAT(3, 0);
+
+// Some of these implementations need to be inlined.
+
+// We separate the declaration from the implementation of this inline
+// function just so the PRINTF_FORMAT works.
+inline int snprintf(char* buffer, size_t size, const char* format, ...)
+    PRINTF_FORMAT(3, 4);
+inline int snprintf(char* buffer, size_t size, const char* format, ...) {
+  va_list arguments;
+  va_start(arguments, format);
+  int result = vsnprintf(buffer, size, format, arguments);
+  va_end(arguments);
+  return result;
+}
+
+// BSD-style safe and consistent string copy functions.
+// Copies |src| to |dst|, where |dst_size| is the total allocated size of |dst|.
+// Copies at most |dst_size|-1 characters, and always NULL terminates |dst|, as
+// long as |dst_size| is not 0.  Returns the length of |src| in characters.
+// If the return value is >= dst_size, then the output was truncated.
+// NOTE: All sizes are in number of characters, NOT in bytes.
+BASE_EXPORT size_t strlcpy(char* dst, const char* src, size_t dst_size);
+BASE_EXPORT size_t wcslcpy(wchar_t* dst, const wchar_t* src, size_t dst_size);
+
+// Scan a wprintf format string to determine whether it's portable across a
+// variety of systems.  This function only checks that the conversion
+// specifiers used by the format string are supported and have the same meaning
+// on a variety of systems.  It doesn't check for other errors that might occur
+// within a format string.
+//
+// Nonportable conversion specifiers for wprintf are:
+//  - 's' and 'c' without an 'l' length modifier.  %s and %c operate on char
+//     data on all systems except Windows, which treat them as wchar_t data.
+//     Use %ls and %lc for wchar_t data instead.
+//  - 'S' and 'C', which operate on wchar_t data on all systems except Windows,
+//     which treat them as char data.  Use %ls and %lc for wchar_t data
+//     instead.
+//  - 'F', which is not identified by Windows wprintf documentation.
+//  - 'D', 'O', and 'U', which are deprecated and not available on all systems.
+//     Use %ld, %lo, and %lu instead.
+//
+// Note that there is no portable conversion specifier for char data when
+// working with wprintf.
+//
+// This function is intended to be called from base::vswprintf.
+BASE_EXPORT bool IsWprintfFormatPortable(const wchar_t* format);
+
+// ASCII-specific tolower.  The standard library's tolower is locale sensitive,
+// so we don't want to use it here.
+inline char ToLowerASCII(char c) {
+  return (c >= 'A' && c <= 'Z') ? (c + ('a' - 'A')) : c;
+}
+inline char16 ToLowerASCII(char16 c) {
+  return (c >= 'A' && c <= 'Z') ? (c + ('a' - 'A')) : c;
+}
+
+// ASCII-specific toupper.  The standard library's toupper is locale sensitive,
+// so we don't want to use it here.
+inline char ToUpperASCII(char c) {
+  return (c >= 'a' && c <= 'z') ? (c + ('A' - 'a')) : c;
+}
+inline char16 ToUpperASCII(char16 c) {
+  return (c >= 'a' && c <= 'z') ? (c + ('A' - 'a')) : c;
+}
+
+// Converts the given string to it's ASCII-lowercase equivalent.
+BASE_EXPORT std::string ToLowerASCII(StringPiece str);
+BASE_EXPORT string16 ToLowerASCII(StringPiece16 str);
+
+// Converts the given string to it's ASCII-uppercase equivalent.
+BASE_EXPORT std::string ToUpperASCII(StringPiece str);
+BASE_EXPORT string16 ToUpperASCII(StringPiece16 str);
+
+// Functor for case-insensitive ASCII comparisons for STL algorithms like
+// std::search.
+//
+// Note that a full Unicode version of this functor is not possible to write
+// because case mappings might change the number of characters, depend on
+// context (combining accents), and require handling UTF-16. If you need
+// proper Unicode support, use base::i18n::ToLower/FoldCase and then just
+// use a normal operator== on the result.
+template<typename Char> struct CaseInsensitiveCompareASCII {
+ public:
+  bool operator()(Char x, Char y) const {
+    return ToLowerASCII(x) == ToLowerASCII(y);
+  }
+};
+
+// Like strcasecmp for case-insensitive ASCII characters only. Returns:
+//   -1  (a < b)
+//    0  (a == b)
+//    1  (a > b)
+// (unlike strcasecmp which can return values greater or less than 1/-1). For
+// full Unicode support, use base::i18n::ToLower or base::i18h::FoldCase
+// and then just call the normal string operators on the result.
+BASE_EXPORT int CompareCaseInsensitiveASCII(StringPiece a, StringPiece b);
+BASE_EXPORT int CompareCaseInsensitiveASCII(StringPiece16 a, StringPiece16 b);
+
+// Equality for ASCII case-insensitive comparisons. For full Unicode support,
+// use base::i18n::ToLower or base::i18h::FoldCase and then compare with either
+// == or !=.
+BASE_EXPORT bool EqualsCaseInsensitiveASCII(StringPiece a, StringPiece b);
+BASE_EXPORT bool EqualsCaseInsensitiveASCII(StringPiece16 a, StringPiece16 b);
+
+// These threadsafe functions return references to globally unique empty
+// strings.
+//
+// It is likely faster to construct a new empty string object (just a few
+// instructions to set the length to 0) than to get the empty string instance
+// returned by these functions (which requires threadsafe static access).
+//
+// Therefore, DO NOT USE THESE AS A GENERAL-PURPOSE SUBSTITUTE FOR DEFAULT
+// CONSTRUCTORS. There is only one case where you should use these: functions
+// which need to return a string by reference (e.g. as a class member
+// accessor), and don't have an empty string to use (e.g. in an error case).
+// These should not be used as initializers, function arguments, or return
+// values for functions which return by value or outparam.
+BASE_EXPORT const std::string& EmptyString();
+BASE_EXPORT const string16& EmptyString16();
+
+// Contains the set of characters representing whitespace in the corresponding
+// encoding. Null-terminated. The ASCII versions are the whitespaces as defined
+// by HTML5, and don't include control characters.
+BASE_EXPORT extern const wchar_t kWhitespaceWide[];  // Includes Unicode.
+BASE_EXPORT extern const char16 kWhitespaceUTF16[];  // Includes Unicode.
+BASE_EXPORT extern const char16 kWhitespaceNoCrLfUTF16[];  // Unicode w/o CR/LF.
+BASE_EXPORT extern const char kWhitespaceASCII[];
+BASE_EXPORT extern const char16 kWhitespaceASCIIAs16[];  // No unicode.
+
+// Null-terminated string representing the UTF-8 byte order mark.
+BASE_EXPORT extern const char kUtf8ByteOrderMark[];
+
+// Removes characters in |remove_chars| from anywhere in |input|.  Returns true
+// if any characters were removed.  |remove_chars| must be null-terminated.
+// NOTE: Safe to use the same variable for both |input| and |output|.
+BASE_EXPORT bool RemoveChars(const string16& input,
+                             StringPiece16 remove_chars,
+                             string16* output);
+BASE_EXPORT bool RemoveChars(const std::string& input,
+                             StringPiece remove_chars,
+                             std::string* output);
+
+// Replaces characters in |replace_chars| from anywhere in |input| with
+// |replace_with|.  Each character in |replace_chars| will be replaced with
+// the |replace_with| string.  Returns true if any characters were replaced.
+// |replace_chars| must be null-terminated.
+// NOTE: Safe to use the same variable for both |input| and |output|.
+BASE_EXPORT bool ReplaceChars(const string16& input,
+                              StringPiece16 replace_chars,
+                              StringPiece16 replace_with,
+                              string16* output);
+BASE_EXPORT bool ReplaceChars(const std::string& input,
+                              StringPiece replace_chars,
+                              StringPiece replace_with,
+                              std::string* output);
+
+enum TrimPositions {
+  TRIM_NONE     = 0,
+  TRIM_LEADING  = 1 << 0,
+  TRIM_TRAILING = 1 << 1,
+  TRIM_ALL      = TRIM_LEADING | TRIM_TRAILING,
+};
+
+// Removes characters in |trim_chars| from the beginning and end of |input|.
+// The 8-bit version only works on 8-bit characters, not UTF-8. Returns true if
+// any characters were removed.
+//
+// It is safe to use the same variable for both |input| and |output| (this is
+// the normal usage to trim in-place).
+BASE_EXPORT bool TrimString(StringPiece16 input,
+                            StringPiece16 trim_chars,
+                            string16* output);
+BASE_EXPORT bool TrimString(StringPiece input,
+                            StringPiece trim_chars,
+                            std::string* output);
+
+// StringPiece versions of the above. The returned pieces refer to the original
+// buffer.
+BASE_EXPORT StringPiece16 TrimString(StringPiece16 input,
+                                     StringPiece16 trim_chars,
+                                     TrimPositions positions);
+BASE_EXPORT StringPiece TrimString(StringPiece input,
+                                   StringPiece trim_chars,
+                                   TrimPositions positions);
+
+// Truncates a string to the nearest UTF-8 character that will leave
+// the string less than or equal to the specified byte size.
+BASE_EXPORT void TruncateUTF8ToByteSize(const std::string& input,
+                                        const size_t byte_size,
+                                        std::string* output);
+
+#if defined(WCHAR_T_IS_UTF16)
+// Utility functions to access the underlying string buffer as a wide char
+// pointer.
+//
+// Note: These functions violate strict aliasing when char16 and wchar_t are
+// unrelated types. We thus pass -fno-strict-aliasing to the compiler on
+// non-Windows platforms [1], and rely on it being off in Clang's CL mode [2].
+//
+// [1] https://crrev.com/b9a0976622/build/config/compiler/BUILD.gn#244
+// [2]
+// https://github.com/llvm/llvm-project/blob/1e28a66/clang/lib/Driver/ToolChains/Clang.cpp#L3949
+inline wchar_t* as_writable_wcstr(char16* str) {
+  return reinterpret_cast<wchar_t*>(str);
+}
+
+inline wchar_t* as_writable_wcstr(string16& str) {
+  return reinterpret_cast<wchar_t*>(data(str));
+}
+
+inline const wchar_t* as_wcstr(const char16* str) {
+  return reinterpret_cast<const wchar_t*>(str);
+}
+
+inline const wchar_t* as_wcstr(StringPiece16 str) {
+  return reinterpret_cast<const wchar_t*>(str.data());
+}
+
+// Utility functions to access the underlying string buffer as a char16 pointer.
+inline char16* as_writable_u16cstr(wchar_t* str) {
+  return reinterpret_cast<char16*>(str);
+}
+
+inline char16* as_writable_u16cstr(std::wstring& str) {
+  return reinterpret_cast<char16*>(data(str));
+}
+
+inline const char16* as_u16cstr(const wchar_t* str) {
+  return reinterpret_cast<const char16*>(str);
+}
+
+inline const char16* as_u16cstr(WStringPiece str) {
+  return reinterpret_cast<const char16*>(str.data());
+}
+
+// Utility functions to convert between base::WStringPiece and
+// base::StringPiece16.
+inline WStringPiece AsWStringPiece(StringPiece16 str) {
+  return WStringPiece(as_wcstr(str.data()), str.size());
+}
+
+inline StringPiece16 AsStringPiece16(WStringPiece str) {
+  return StringPiece16(as_u16cstr(str.data()), str.size());
+}
+
+inline std::wstring AsWString(StringPiece16 str) {
+  return std::wstring(as_wcstr(str.data()), str.size());
+}
+
+inline string16 AsString16(WStringPiece str) {
+  return string16(as_u16cstr(str.data()), str.size());
+}
+#endif  // defined(WCHAR_T_IS_UTF16)
+
+// Trims any whitespace from either end of the input string.
+//
+// The StringPiece versions return a substring referencing the input buffer.
+// The ASCII versions look only for ASCII whitespace.
+//
+// The std::string versions return where whitespace was found.
+// NOTE: Safe to use the same variable for both input and output.
+BASE_EXPORT TrimPositions TrimWhitespace(StringPiece16 input,
+                                         TrimPositions positions,
+                                         string16* output);
+BASE_EXPORT StringPiece16 TrimWhitespace(StringPiece16 input,
+                                         TrimPositions positions);
+BASE_EXPORT TrimPositions TrimWhitespaceASCII(StringPiece input,
+                                              TrimPositions positions,
+                                              std::string* output);
+BASE_EXPORT StringPiece TrimWhitespaceASCII(StringPiece input,
+                                            TrimPositions positions);
+
+// Searches for CR or LF characters.  Removes all contiguous whitespace
+// strings that contain them.  This is useful when trying to deal with text
+// copied from terminals.
+// Returns |text|, with the following three transformations:
+// (1) Leading and trailing whitespace is trimmed.
+// (2) If |trim_sequences_with_line_breaks| is true, any other whitespace
+//     sequences containing a CR or LF are trimmed.
+// (3) All other whitespace sequences are converted to single spaces.
+BASE_EXPORT string16 CollapseWhitespace(
+    const string16& text,
+    bool trim_sequences_with_line_breaks);
+BASE_EXPORT std::string CollapseWhitespaceASCII(
+    const std::string& text,
+    bool trim_sequences_with_line_breaks);
+
+// Returns true if |input| is empty or contains only characters found in
+// |characters|.
+BASE_EXPORT bool ContainsOnlyChars(StringPiece input, StringPiece characters);
+BASE_EXPORT bool ContainsOnlyChars(StringPiece16 input,
+                                   StringPiece16 characters);
+
+// Returns true if |str| is structurally valid UTF-8 and also doesn't
+// contain any non-character code point (e.g. U+10FFFE). Prohibiting
+// non-characters increases the likelihood of detecting non-UTF-8 in
+// real-world text, for callers which do not need to accept
+// non-characters in strings.
+BASE_EXPORT bool IsStringUTF8(StringPiece str);
+
+// Returns true if |str| contains valid UTF-8, allowing non-character
+// code points.
+BASE_EXPORT bool IsStringUTF8AllowingNoncharacters(StringPiece str);
+
+// Returns true if |str| contains only valid ASCII character values.
+// Note 1: IsStringASCII executes in time determined solely by the
+// length of the string, not by its contents, so it is robust against
+// timing attacks for all strings of equal length.
+// Note 2: IsStringASCII assumes the input is likely all ASCII, and
+// does not leave early if it is not the case.
+BASE_EXPORT bool IsStringASCII(StringPiece str);
+BASE_EXPORT bool IsStringASCII(StringPiece16 str);
+#if defined(WCHAR_T_IS_UTF32)
+BASE_EXPORT bool IsStringASCII(WStringPiece str);
+#endif
+
+// Compare the lower-case form of the given string against the given
+// previously-lower-cased ASCII string (typically a constant).
+BASE_EXPORT bool LowerCaseEqualsASCII(StringPiece str,
+                                      StringPiece lowecase_ascii);
+BASE_EXPORT bool LowerCaseEqualsASCII(StringPiece16 str,
+                                      StringPiece lowecase_ascii);
+
+// Performs a case-sensitive string compare of the given 16-bit string against
+// the given 8-bit ASCII string (typically a constant). The behavior is
+// undefined if the |ascii| string is not ASCII.
+BASE_EXPORT bool EqualsASCII(StringPiece16 str, StringPiece ascii);
+
+// Indicates case sensitivity of comparisons. Only ASCII case insensitivity
+// is supported. Full Unicode case-insensitive conversions would need to go in
+// base/i18n so it can use ICU.
+//
+// If you need to do Unicode-aware case-insensitive StartsWith/EndsWith, it's
+// best to call base::i18n::ToLower() or base::i18n::FoldCase() (see
+// base/i18n/case_conversion.h for usage advice) on the arguments, and then use
+// the results to a case-sensitive comparison.
+enum class CompareCase {
+  SENSITIVE,
+  INSENSITIVE_ASCII,
+};
+
+BASE_EXPORT bool StartsWith(StringPiece str,
+                            StringPiece search_for,
+                            CompareCase case_sensitivity);
+BASE_EXPORT bool StartsWith(StringPiece16 str,
+                            StringPiece16 search_for,
+                            CompareCase case_sensitivity);
+BASE_EXPORT bool EndsWith(StringPiece str,
+                          StringPiece search_for,
+                          CompareCase case_sensitivity);
+BASE_EXPORT bool EndsWith(StringPiece16 str,
+                          StringPiece16 search_for,
+                          CompareCase case_sensitivity);
+
+// Determines the type of ASCII character, independent of locale (the C
+// library versions will change based on locale).
+template <typename Char>
+inline bool IsAsciiWhitespace(Char c) {
+  return c == ' ' || c == '\r' || c == '\n' || c == '\t' || c == '\f';
+}
+template <typename Char>
+inline bool IsAsciiAlpha(Char c) {
+  return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
+}
+template <typename Char>
+inline bool IsAsciiUpper(Char c) {
+  return c >= 'A' && c <= 'Z';
+}
+template <typename Char>
+inline bool IsAsciiLower(Char c) {
+  return c >= 'a' && c <= 'z';
+}
+template <typename Char>
+inline bool IsAsciiDigit(Char c) {
+  return c >= '0' && c <= '9';
+}
+template <typename Char>
+inline bool IsAsciiPrintable(Char c) {
+  return c >= ' ' && c <= '~';
+}
+
+template <typename Char>
+inline bool IsHexDigit(Char c) {
+  return (c >= '0' && c <= '9') ||
+         (c >= 'A' && c <= 'F') ||
+         (c >= 'a' && c <= 'f');
+}
+
+// Returns the integer corresponding to the given hex character. For example:
+//    '4' -> 4
+//    'a' -> 10
+//    'B' -> 11
+// Assumes the input is a valid hex character. DCHECKs in debug builds if not.
+BASE_EXPORT char HexDigitToInt(wchar_t c);
+
+// Returns true if it's a Unicode whitespace character.
+BASE_EXPORT bool IsUnicodeWhitespace(wchar_t c);
+
+// Return a byte string in human-readable format with a unit suffix. Not
+// appropriate for use in any UI; use of FormatBytes and friends in ui/base is
+// highly recommended instead. TODO(avi): Figure out how to get callers to use
+// FormatBytes instead; remove this.
+BASE_EXPORT string16 FormatBytesUnlocalized(int64_t bytes);
+
+// Starting at |start_offset| (usually 0), replace the first instance of
+// |find_this| with |replace_with|.
+BASE_EXPORT void ReplaceFirstSubstringAfterOffset(
+    base::string16* str,
+    size_t start_offset,
+    StringPiece16 find_this,
+    StringPiece16 replace_with);
+BASE_EXPORT void ReplaceFirstSubstringAfterOffset(
+    std::string* str,
+    size_t start_offset,
+    StringPiece find_this,
+    StringPiece replace_with);
+
+// Starting at |start_offset| (usually 0), look through |str| and replace all
+// instances of |find_this| with |replace_with|.
+//
+// This does entire substrings; use std::replace in <algorithm> for single
+// characters, for example:
+//   std::replace(str.begin(), str.end(), 'a', 'b');
+BASE_EXPORT void ReplaceSubstringsAfterOffset(
+    string16* str,
+    size_t start_offset,
+    StringPiece16 find_this,
+    StringPiece16 replace_with);
+BASE_EXPORT void ReplaceSubstringsAfterOffset(
+    std::string* str,
+    size_t start_offset,
+    StringPiece find_this,
+    StringPiece replace_with);
+
+// Reserves enough memory in |str| to accommodate |length_with_null| characters,
+// sets the size of |str| to |length_with_null - 1| characters, and returns a
+// pointer to the underlying contiguous array of characters.  This is typically
+// used when calling a function that writes results into a character array, but
+// the caller wants the data to be managed by a string-like object.  It is
+// convenient in that is can be used inline in the call, and fast in that it
+// avoids copying the results of the call from a char* into a string.
+//
+// Internally, this takes linear time because the resize() call 0-fills the
+// underlying array for potentially all
+// (|length_with_null - 1| * sizeof(string_type::value_type)) bytes.  Ideally we
+// could avoid this aspect of the resize() call, as we expect the caller to
+// immediately write over this memory, but there is no other way to set the size
+// of the string, and not doing that will mean people who access |str| rather
+// than str.c_str() will get back a string of whatever size |str| had on entry
+// to this function (probably 0).
+BASE_EXPORT char* WriteInto(std::string* str, size_t length_with_null);
+BASE_EXPORT char16* WriteInto(string16* str, size_t length_with_null);
+
+// Joins a vector or list of strings into a single string, inserting |separator|
+// (which may be empty) in between all elements.
+//
+// Note this is inverse of SplitString()/SplitStringPiece() defined in
+// string_split.h.
+//
+// If possible, callers should build a vector of StringPieces and use the
+// StringPiece variant, so that they do not create unnecessary copies of
+// strings. For example, instead of using SplitString, modifying the vector,
+// then using JoinString, use SplitStringPiece followed by JoinString so that no
+// copies of those strings are created until the final join operation.
+//
+// Use StrCat (in base/strings/strcat.h) if you don't need a separator.
+BASE_EXPORT std::string JoinString(const std::vector<std::string>& parts,
+                                   StringPiece separator);
+BASE_EXPORT string16 JoinString(const std::vector<string16>& parts,
+                                StringPiece16 separator);
+BASE_EXPORT std::string JoinString(const std::vector<StringPiece>& parts,
+                                   StringPiece separator);
+BASE_EXPORT string16 JoinString(const std::vector<StringPiece16>& parts,
+                                StringPiece16 separator);
+// Explicit initializer_list overloads are required to break ambiguity when used
+// with a literal initializer list (otherwise the compiler would not be able to
+// decide between the string and StringPiece overloads).
+BASE_EXPORT std::string JoinString(std::initializer_list<StringPiece> parts,
+                                   StringPiece separator);
+BASE_EXPORT string16 JoinString(std::initializer_list<StringPiece16> parts,
+                                StringPiece16 separator);
+
+// Replace $1-$2-$3..$9 in the format string with values from |subst|.
+// Additionally, any number of consecutive '$' characters is replaced by that
+// number less one. Eg $$->$, $$$->$$, etc. The offsets parameter here can be
+// NULL. This only allows you to use up to nine replacements.
+BASE_EXPORT string16 ReplaceStringPlaceholders(
+    const string16& format_string,
+    const std::vector<string16>& subst,
+    std::vector<size_t>* offsets);
+
+BASE_EXPORT std::string ReplaceStringPlaceholders(
+    StringPiece format_string,
+    const std::vector<std::string>& subst,
+    std::vector<size_t>* offsets);
+
+// Single-string shortcut for ReplaceStringHolders. |offset| may be NULL.
+BASE_EXPORT string16 ReplaceStringPlaceholders(const string16& format_string,
+                                               const string16& a,
+                                               size_t* offset);
+
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+BASE_EXPORT TrimPositions TrimWhitespace(WStringPiece input,
+                                         TrimPositions positions,
+                                         std::wstring* output);
+
+BASE_EXPORT WStringPiece TrimWhitespace(WStringPiece input,
+                                        TrimPositions positions);
+
+BASE_EXPORT bool TrimString(WStringPiece input,
+                            WStringPiece trim_chars,
+                            std::wstring* output);
+
+BASE_EXPORT WStringPiece TrimString(WStringPiece input,
+                                    WStringPiece trim_chars,
+                                    TrimPositions positions);
+
+BASE_EXPORT wchar_t* WriteInto(std::wstring* str, size_t length_with_null);
+#endif
+
+}  // namespace base
+
+#if defined(OS_WIN)
+#include "base/strings/string_util_win.h"
+#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
+#include "base/strings/string_util_posix.h"
+#else
+#error Define string operations appropriately for your platform
+#endif
+
+#endif  // BASE_STRINGS_STRING_UTIL_H_
diff --git a/security/sandbox/chromium/base/strings/string_util_constants.cc b/security/sandbox/chromium/base/strings/string_util_constants.cc
new file mode 100644
index 0000000000..212c5ab082
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_util_constants.cc
@@ -0,0 +1,54 @@
+// 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.
+
+#include "base/strings/string_util.h"
+
+namespace base {
+
+#define WHITESPACE_ASCII_NO_CR_LF      \
+  0x09,     /* CHARACTER TABULATION */ \
+      0x0B, /* LINE TABULATION */      \
+      0x0C, /* FORM FEED (FF) */       \
+      0x20  /* SPACE */
+
+#define WHITESPACE_ASCII                                                  \
+  WHITESPACE_ASCII_NO_CR_LF, /* Comment to make clang-format linebreak */ \
+      0x0A,                  /* LINE FEED (LF) */                         \
+      0x0D                   /* CARRIAGE RETURN (CR) */
+
+#define WHITESPACE_UNICODE_NON_ASCII          \
+  0x0085,     /* NEXT LINE (NEL) */           \
+      0x00A0, /* NO-BREAK SPACE */            \
+      0x1680, /* OGHAM SPACE MARK */          \
+      0x2000, /* EN QUAD */                   \
+      0x2001, /* EM QUAD */                   \
+      0x2002, /* EN SPACE */                  \
+      0x2003, /* EM SPACE */                  \
+      0x2004, /* THREE-PER-EM SPACE */        \
+      0x2005, /* FOUR-PER-EM SPACE */         \
+      0x2006, /* SIX-PER-EM SPACE */          \
+      0x2007, /* FIGURE SPACE */              \
+      0x2008, /* PUNCTUATION SPACE */         \
+      0x2009, /* THIN SPACE */                \
+      0x200A, /* HAIR SPACE */                \
+      0x2028, /* LINE SEPARATOR */            \
+      0x2029, /* PARAGRAPH SEPARATOR */       \
+      0x202F, /* NARROW NO-BREAK SPACE */     \
+      0x205F, /* MEDIUM MATHEMATICAL SPACE */ \
+      0x3000  /* IDEOGRAPHIC SPACE */
+
+#define WHITESPACE_UNICODE_NO_CR_LF \
+  WHITESPACE_ASCII_NO_CR_LF, WHITESPACE_UNICODE_NON_ASCII
+
+#define WHITESPACE_UNICODE WHITESPACE_ASCII, WHITESPACE_UNICODE_NON_ASCII
+
+const wchar_t kWhitespaceWide[] = {WHITESPACE_UNICODE, 0};
+const char16 kWhitespaceUTF16[] = {WHITESPACE_UNICODE, 0};
+const char16 kWhitespaceNoCrLfUTF16[] = {WHITESPACE_UNICODE_NO_CR_LF, 0};
+const char kWhitespaceASCII[] = {WHITESPACE_ASCII, 0};
+const char16 kWhitespaceASCIIAs16[] = {WHITESPACE_ASCII, 0};
+
+const char kUtf8ByteOrderMark[] = "\xEF\xBB\xBF";
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/string_util_posix.h b/security/sandbox/chromium/base/strings/string_util_posix.h
new file mode 100644
index 0000000000..8299118e10
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_util_posix.h
@@ -0,0 +1,37 @@
+// 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_STRING_UTIL_POSIX_H_
+#define BASE_STRINGS_STRING_UTIL_POSIX_H_
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <wchar.h>
+
+#include "base/logging.h"
+
+namespace base {
+
+// Chromium code style is to not use malloc'd strings; this is only for use
+// for interaction with APIs that require it.
+inline char* strdup(const char* str) {
+  return ::strdup(str);
+}
+
+inline int vsnprintf(char* buffer, size_t size,
+                     const char* format, va_list arguments) {
+  return ::vsnprintf(buffer, size, format, arguments);
+}
+
+inline int vswprintf(wchar_t* buffer, size_t size,
+                     const wchar_t* format, va_list arguments) {
+  DCHECK(IsWprintfFormatPortable(format));
+  return ::vswprintf(buffer, size, format, arguments);
+}
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRING_UTIL_POSIX_H_
diff --git a/security/sandbox/chromium/base/strings/string_util_win.h b/security/sandbox/chromium/base/strings/string_util_win.h
new file mode 100644
index 0000000000..7f260bfc8b
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string_util_win.h
@@ -0,0 +1,44 @@
+// 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_STRING_UTIL_WIN_H_
+#define BASE_STRINGS_STRING_UTIL_WIN_H_
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <wchar.h>
+
+#include "base/logging.h"
+
+namespace base {
+
+// Chromium code style is to not use malloc'd strings; this is only for use
+// for interaction with APIs that require it.
+inline char* strdup(const char* str) {
+  return _strdup(str);
+}
+
+inline int vsnprintf(char* buffer, size_t size,
+                     const char* format, va_list arguments) {
+  int length = vsnprintf_s(buffer, size, size - 1, format, arguments);
+  if (length < 0)
+    return _vscprintf(format, arguments);
+  return length;
+}
+
+inline int vswprintf(wchar_t* buffer, size_t size,
+                     const wchar_t* format, va_list arguments) {
+  DCHECK(IsWprintfFormatPortable(format));
+
+  int length = _vsnwprintf_s(buffer, size, size - 1, format, arguments);
+  if (length < 0)
+    return _vscwprintf(format, arguments);
+  return length;
+}
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRING_UTIL_WIN_H_
diff --git a/security/sandbox/chromium/base/strings/stringprintf.cc b/security/sandbox/chromium/base/strings/stringprintf.cc
new file mode 100644
index 0000000000..738cc63bbe
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/stringprintf.cc
@@ -0,0 +1,225 @@
+// 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.
+
+#include "base/strings/stringprintf.h"
+
+#include <errno.h>
+#include <stddef.h>
+
+#include <vector>
+
+#include "base/scoped_clear_last_error.h"
+#include "base/stl_util.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "build/build_config.h"
+
+namespace base {
+
+namespace {
+
+// Overloaded wrappers around vsnprintf and vswprintf. The buf_size parameter
+// is the size of the buffer. These return the number of characters in the
+// formatted string excluding the NUL terminator. If the buffer is not
+// large enough to accommodate the formatted string without truncation, they
+// return the number of characters that would be in the fully-formatted string
+// (vsnprintf, and vswprintf on Windows), or -1 (vswprintf on POSIX platforms).
+inline int vsnprintfT(char* buffer,
+                      size_t buf_size,
+                      const char* format,
+                      va_list argptr) {
+  return base::vsnprintf(buffer, buf_size, format, argptr);
+}
+
+#if defined(OS_WIN)
+inline int vsnprintfT(wchar_t* buffer,
+                      size_t buf_size,
+                      const wchar_t* format,
+                      va_list argptr) {
+  return base::vswprintf(buffer, buf_size, format, argptr);
+}
+inline int vsnprintfT(char16_t* buffer,
+                      size_t buf_size,
+                      const char16_t* format,
+                      va_list argptr) {
+  return base::vswprintf(reinterpret_cast<wchar_t*>(buffer), buf_size,
+                         reinterpret_cast<const wchar_t*>(format), argptr);
+}
+#endif
+
+// Templatized backend for StringPrintF/StringAppendF. This does not finalize
+// the va_list, the caller is expected to do that.
+template <class CharT>
+static void StringAppendVT(std::basic_string<CharT>* dst,
+                           const CharT* format,
+                           va_list ap) {
+  // First try with a small fixed size buffer.
+  // This buffer size should be kept in sync with StringUtilTest.GrowBoundary
+  // and StringUtilTest.StringPrintfBounds.
+  CharT stack_buf[1024];
+
+  va_list ap_copy;
+  va_copy(ap_copy, ap);
+
+  base::internal::ScopedClearLastError last_error;
+  int result = vsnprintfT(stack_buf, base::size(stack_buf), format, ap_copy);
+  va_end(ap_copy);
+
+  if (result >= 0 && result < static_cast<int>(base::size(stack_buf))) {
+    // It fit.
+    dst->append(stack_buf, result);
+    return;
+  }
+
+  // Repeatedly increase buffer size until it fits.
+  int mem_length = base::size(stack_buf);
+  while (true) {
+    if (result < 0) {
+#if defined(OS_WIN)
+      // On Windows, vsnprintfT always returns the number of characters in a
+      // fully-formatted string, so if we reach this point, something else is
+      // wrong and no amount of buffer-doubling is going to fix it.
+      return;
+#else
+      if (errno != 0 && errno != EOVERFLOW)
+        return;
+      // Try doubling the buffer size.
+      mem_length *= 2;
+#endif
+    } else {
+      // We need exactly "result + 1" characters.
+      mem_length = result + 1;
+    }
+
+    if (mem_length > 32 * 1024 * 1024) {
+      // That should be plenty, don't try anything larger.  This protects
+      // against huge allocations when using vsnprintfT implementations that
+      // return -1 for reasons other than overflow without setting errno.
+      DLOG(WARNING) << "Unable to printf the requested string due to size.";
+      return;
+    }
+
+    std::vector<CharT> mem_buf(mem_length);
+
+    // NOTE: You can only use a va_list once.  Since we're in a while loop, we
+    // need to make a new copy each time so we don't use up the original.
+    va_copy(ap_copy, ap);
+    result = vsnprintfT(&mem_buf[0], mem_length, format, ap_copy);
+    va_end(ap_copy);
+
+    if ((result >= 0) && (result < mem_length)) {
+      // It fit.
+      dst->append(&mem_buf[0], result);
+      return;
+    }
+  }
+}
+
+}  // namespace
+
+std::string StringPrintf(const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  std::string result;
+  StringAppendV(&result, format, ap);
+  va_end(ap);
+  return result;
+}
+
+#if defined(OS_WIN)
+std::wstring StringPrintf(const wchar_t* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  std::wstring result;
+  StringAppendV(&result, format, ap);
+  va_end(ap);
+  return result;
+}
+
+std::u16string StringPrintf(const char16_t* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  std::u16string result;
+  StringAppendV(&result, format, ap);
+  va_end(ap);
+  return result;
+}
+#endif
+
+std::string StringPrintV(const char* format, va_list ap) {
+  std::string result;
+  StringAppendV(&result, format, ap);
+  return result;
+}
+
+const std::string& SStringPrintf(std::string* dst, const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  dst->clear();
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+  return *dst;
+}
+
+#if defined(OS_WIN)
+const std::wstring& SStringPrintf(std::wstring* dst,
+                                  const wchar_t* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  dst->clear();
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+  return *dst;
+}
+
+const std::u16string& SStringPrintf(std::u16string* dst,
+                                    const char16_t* format,
+                                    ...) {
+  va_list ap;
+  va_start(ap, format);
+  dst->clear();
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+  return *dst;
+}
+#endif
+
+void StringAppendF(std::string* dst, const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+}
+
+#if defined(OS_WIN)
+void StringAppendF(std::wstring* dst, const wchar_t* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+}
+
+void StringAppendF(std::u16string* dst, const char16_t* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+}
+#endif
+
+void StringAppendV(std::string* dst, const char* format, va_list ap) {
+  StringAppendVT(dst, format, ap);
+}
+
+#if defined(OS_WIN)
+void StringAppendV(std::wstring* dst, const wchar_t* format, va_list ap) {
+  StringAppendVT(dst, format, ap);
+}
+
+void StringAppendV(std::u16string* dst, const char16_t* format, va_list ap) {
+  StringAppendVT(dst, format, ap);
+}
+#endif
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/stringprintf.h b/security/sandbox/chromium/base/strings/stringprintf.h
new file mode 100644
index 0000000000..a8d5bc84e9
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/stringprintf.h
@@ -0,0 +1,74 @@
+// 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"
+#include "build/build_config.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)
+// Note: Unfortunately compile time checking of the format string for UTF-16
+// strings is not supported by any compiler, thus these functions should be used
+// carefully and sparingly. Also applies to SStringPrintf and StringAppendV
+// below.
+BASE_EXPORT std::wstring StringPrintf(const wchar_t* format, ...)
+    WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
+BASE_EXPORT std::u16string StringPrintf(const char16_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);
+BASE_EXPORT const std::u16string& SStringPrintf(std::u16string* dst,
+                                                const char16_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);
+BASE_EXPORT void StringAppendF(std::u16string* dst, const char16_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);
+BASE_EXPORT void StringAppendV(std::u16string* dst,
+                               const char16_t* format,
+                               va_list ap) WPRINTF_FORMAT(2, 0);
+#endif
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRINGPRINTF_H_
diff --git a/security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc b/security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc
new file mode 100644
index 0000000000..f7682c1be9
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc
@@ -0,0 +1,155 @@
+// Copyright (c) 2009 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/strings/utf_string_conversion_utils.h"
+
+#include "base/third_party/icu/icu_utf.h"
+#include "build/build_config.h"
+
+namespace base {
+
+// ReadUnicodeCharacter --------------------------------------------------------
+
+bool ReadUnicodeCharacter(const char* src,
+                          int32_t src_len,
+                          int32_t* char_index,
+                          uint32_t* code_point_out) {
+  // U8_NEXT expects to be able to use -1 to signal an error, so we must
+  // use a signed type for code_point.  But this function returns false
+  // on error anyway, so code_point_out is unsigned.
+  int32_t code_point;
+  CBU8_NEXT(src, *char_index, src_len, code_point);
+  *code_point_out = static_cast<uint32_t>(code_point);
+
+  // The ICU macro above moves to the next char, we want to point to the last
+  // char consumed.
+  (*char_index)--;
+
+  // Validate the decoded value.
+  return IsValidCodepoint(code_point);
+}
+
+bool ReadUnicodeCharacter(const char16* src,
+                          int32_t src_len,
+                          int32_t* char_index,
+                          uint32_t* code_point) {
+  if (CBU16_IS_SURROGATE(src[*char_index])) {
+    if (!CBU16_IS_SURROGATE_LEAD(src[*char_index]) ||
+        *char_index + 1 >= src_len ||
+        !CBU16_IS_TRAIL(src[*char_index + 1])) {
+      // Invalid surrogate pair.
+      return false;
+    }
+
+    // Valid surrogate pair.
+    *code_point = CBU16_GET_SUPPLEMENTARY(src[*char_index],
+                                          src[*char_index + 1]);
+    (*char_index)++;
+  } else {
+    // Not a surrogate, just one 16-bit word.
+    *code_point = src[*char_index];
+  }
+
+  return IsValidCodepoint(*code_point);
+}
+
+#if defined(WCHAR_T_IS_UTF32)
+bool ReadUnicodeCharacter(const wchar_t* src,
+                          int32_t src_len,
+                          int32_t* char_index,
+                          uint32_t* code_point) {
+  // Conversion is easy since the source is 32-bit.
+  *code_point = src[*char_index];
+
+  // Validate the value.
+  return IsValidCodepoint(*code_point);
+}
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+// WriteUnicodeCharacter -------------------------------------------------------
+
+size_t WriteUnicodeCharacter(uint32_t code_point, std::string* output) {
+  if (code_point <= 0x7f) {
+    // Fast path the common case of one byte.
+    output->push_back(static_cast<char>(code_point));
+    return 1;
+  }
+
+
+  // CBU8_APPEND_UNSAFE can append up to 4 bytes.
+  size_t char_offset = output->length();
+  size_t original_char_offset = char_offset;
+  output->resize(char_offset + CBU8_MAX_LENGTH);
+
+  CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
+
+  // CBU8_APPEND_UNSAFE will advance our pointer past the inserted character, so
+  // it will represent the new length of the string.
+  output->resize(char_offset);
+  return char_offset - original_char_offset;
+}
+
+size_t WriteUnicodeCharacter(uint32_t code_point, string16* output) {
+  if (CBU16_LENGTH(code_point) == 1) {
+    // Thie code point is in the Basic Multilingual Plane (BMP).
+    output->push_back(static_cast<char16>(code_point));
+    return 1;
+  }
+  // Non-BMP characters use a double-character encoding.
+  size_t char_offset = output->length();
+  output->resize(char_offset + CBU16_MAX_LENGTH);
+  CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
+  return CBU16_MAX_LENGTH;
+}
+
+// Generalized Unicode converter -----------------------------------------------
+
+template<typename CHAR>
+void PrepareForUTF8Output(const CHAR* src,
+                          size_t src_len,
+                          std::string* output) {
+  output->clear();
+  if (src_len == 0)
+    return;
+  if (src[0] < 0x80) {
+    // Assume that the entire input will be ASCII.
+    output->reserve(src_len);
+  } else {
+    // Assume that the entire input is non-ASCII and will have 3 bytes per char.
+    output->reserve(src_len * 3);
+  }
+}
+
+// Instantiate versions we know callers will need.
+#if !defined(OS_WIN)
+// wchar_t and char16 are the same thing on Windows.
+template void PrepareForUTF8Output(const wchar_t*, size_t, std::string*);
+#endif
+template void PrepareForUTF8Output(const char16*, size_t, std::string*);
+
+template<typename STRING>
+void PrepareForUTF16Or32Output(const char* src,
+                               size_t src_len,
+                               STRING* output) {
+  output->clear();
+  if (src_len == 0)
+    return;
+  if (static_cast<unsigned char>(src[0]) < 0x80) {
+    // Assume the input is all ASCII, which means 1:1 correspondence.
+    output->reserve(src_len);
+  } else {
+    // Otherwise assume that the UTF-8 sequences will have 2 bytes for each
+    // character.
+    output->reserve(src_len / 2);
+  }
+}
+
+// Instantiate versions we know callers will need.
+#if !defined(OS_WIN)
+// std::wstring and string16 are the same thing on Windows.
+template void PrepareForUTF16Or32Output(const char*, size_t, std::wstring*);
+#endif
+template void PrepareForUTF16Or32Output(const char*, size_t, string16*);
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/utf_string_conversion_utils.h b/security/sandbox/chromium/base/strings/utf_string_conversion_utils.h
new file mode 100644
index 0000000000..01d24c3e2e
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/utf_string_conversion_utils.h
@@ -0,0 +1,103 @@
+// 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_STRINGS_UTF_STRING_CONVERSION_UTILS_H_
+#define BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_
+
+// Low-level UTF handling functions. Most code will want to use the functions
+// in utf_string_conversions.h
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "base/base_export.h"
+#include "base/strings/string16.h"
+
+namespace base {
+
+inline bool IsValidCodepoint(uint32_t code_point) {
+  // Excludes code points that are not Unicode scalar values, i.e.
+  // surrogate code points ([0xD800, 0xDFFF]). Additionally, excludes
+  // code points larger than 0x10FFFF (the highest codepoint allowed).
+  // Non-characters and unassigned code points are allowed.
+  // https://unicode.org/glossary/#unicode_scalar_value
+  return code_point < 0xD800u ||
+         (code_point >= 0xE000u && code_point <= 0x10FFFFu);
+}
+
+inline bool IsValidCharacter(uint32_t code_point) {
+  // Excludes non-characters (U+FDD0..U+FDEF, and all code points
+  // ending in 0xFFFE or 0xFFFF) from the set of valid code points.
+  // https://unicode.org/faq/private_use.html#nonchar1
+  return code_point < 0xD800u || (code_point >= 0xE000u &&
+      code_point < 0xFDD0u) || (code_point > 0xFDEFu &&
+      code_point <= 0x10FFFFu && (code_point & 0xFFFEu) != 0xFFFEu);
+}
+
+// ReadUnicodeCharacter --------------------------------------------------------
+
+// Reads a UTF-8 stream, placing the next code point into the given output
+// |*code_point|. |src| represents the entire string to read, and |*char_index|
+// is the character offset within the string to start reading at. |*char_index|
+// will be updated to index the last character read, such that incrementing it
+// (as in a for loop) will take the reader to the next character.
+//
+// Returns true on success. On false, |*code_point| will be invalid.
+BASE_EXPORT bool ReadUnicodeCharacter(const char* src,
+                                      int32_t src_len,
+                                      int32_t* char_index,
+                                      uint32_t* code_point_out);
+
+// Reads a UTF-16 character. The usage is the same as the 8-bit version above.
+BASE_EXPORT bool ReadUnicodeCharacter(const char16* src,
+                                      int32_t src_len,
+                                      int32_t* char_index,
+                                      uint32_t* code_point);
+
+#if defined(WCHAR_T_IS_UTF32)
+// Reads UTF-32 character. The usage is the same as the 8-bit version above.
+BASE_EXPORT bool ReadUnicodeCharacter(const wchar_t* src,
+                                      int32_t src_len,
+                                      int32_t* char_index,
+                                      uint32_t* code_point);
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+// WriteUnicodeCharacter -------------------------------------------------------
+
+// Appends a UTF-8 character to the given 8-bit string.  Returns the number of
+// bytes written.
+BASE_EXPORT size_t WriteUnicodeCharacter(uint32_t code_point,
+                                         std::string* output);
+
+// Appends the given code point as a UTF-16 character to the given 16-bit
+// string.  Returns the number of 16-bit values written.
+BASE_EXPORT size_t WriteUnicodeCharacter(uint32_t code_point, string16* output);
+
+#if defined(WCHAR_T_IS_UTF32)
+// Appends the given UTF-32 character to the given 32-bit string.  Returns the
+// number of 32-bit values written.
+inline size_t WriteUnicodeCharacter(uint32_t code_point, std::wstring* output) {
+  // This is the easy case, just append the character.
+  output->push_back(code_point);
+  return 1;
+}
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+// Generalized Unicode converter -----------------------------------------------
+
+// Guesses the length of the output in UTF-8 in bytes, clears that output
+// string, and reserves that amount of space.  We assume that the input
+// character types are unsigned, which will be true for UTF-16 and -32 on our
+// systems.
+template<typename CHAR>
+void PrepareForUTF8Output(const CHAR* src, size_t src_len, std::string* output);
+
+// Prepares an output buffer (containing either UTF-16 or -32 data) given some
+// UTF-8 input that will be converted to it.  See PrepareForUTF8Output().
+template<typename STRING>
+void PrepareForUTF16Or32Output(const char* src, size_t src_len, STRING* output);
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_
diff --git a/security/sandbox/chromium/base/strings/utf_string_conversions.cc b/security/sandbox/chromium/base/strings/utf_string_conversions.cc
new file mode 100644
index 0000000000..9a79889159
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/utf_string_conversions.cc
@@ -0,0 +1,342 @@
+// Copyright (c) 2018 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/strings/utf_string_conversions.h"
+
+#include <limits.h>
+#include <stdint.h>
+
+#include <type_traits>
+
+#include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversion_utils.h"
+#include "base/third_party/icu/icu_utf.h"
+#include "build/build_config.h"
+
+namespace base {
+
+namespace {
+
+constexpr int32_t kErrorCodePoint = 0xFFFD;
+
+// Size coefficient ----------------------------------------------------------
+// The maximum number of codeunits in the destination encoding corresponding to
+// one codeunit in the source encoding.
+
+template <typename SrcChar, typename DestChar>
+struct SizeCoefficient {
+  static_assert(sizeof(SrcChar) < sizeof(DestChar),
+                "Default case: from a smaller encoding to the bigger one");
+
+  // ASCII symbols are encoded by one codeunit in all encodings.
+  static constexpr int value = 1;
+};
+
+template <>
+struct SizeCoefficient<char16, char> {
+  // One UTF-16 codeunit corresponds to at most 3 codeunits in UTF-8.
+  static constexpr int value = 3;
+};
+
+#if defined(WCHAR_T_IS_UTF32)
+template <>
+struct SizeCoefficient<wchar_t, char> {
+  // UTF-8 uses at most 4 codeunits per character.
+  static constexpr int value = 4;
+};
+
+template <>
+struct SizeCoefficient<wchar_t, char16> {
+  // UTF-16 uses at most 2 codeunits per character.
+  static constexpr int value = 2;
+};
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+template <typename SrcChar, typename DestChar>
+constexpr int size_coefficient_v =
+    SizeCoefficient<std::decay_t<SrcChar>, std::decay_t<DestChar>>::value;
+
+// UnicodeAppendUnsafe --------------------------------------------------------
+// Function overloads that write code_point to the output string. Output string
+// has to have enough space for the codepoint.
+
+// Convenience typedef that checks whether the passed in type is integral (i.e.
+// bool, char, int or their extended versions) and is of the correct size.
+template <typename Char, size_t N>
+using EnableIfBitsAre = std::enable_if_t<std::is_integral<Char>::value &&
+                                             CHAR_BIT * sizeof(Char) == N,
+                                         bool>;
+
+template <typename Char, EnableIfBitsAre<Char, 8> = true>
+void UnicodeAppendUnsafe(Char* out, int32_t* size, uint32_t code_point) {
+  CBU8_APPEND_UNSAFE(out, *size, code_point);
+}
+
+template <typename Char, EnableIfBitsAre<Char, 16> = true>
+void UnicodeAppendUnsafe(Char* out, int32_t* size, uint32_t code_point) {
+  CBU16_APPEND_UNSAFE(out, *size, code_point);
+}
+
+template <typename Char, EnableIfBitsAre<Char, 32> = true>
+void UnicodeAppendUnsafe(Char* out, int32_t* size, uint32_t code_point) {
+  out[(*size)++] = code_point;
+}
+
+// DoUTFConversion ------------------------------------------------------------
+// Main driver of UTFConversion specialized for different Src encodings.
+// dest has to have enough room for the converted text.
+
+template <typename DestChar>
+bool DoUTFConversion(const char* src,
+                     int32_t src_len,
+                     DestChar* dest,
+                     int32_t* dest_len) {
+  bool success = true;
+
+  for (int32_t i = 0; i < src_len;) {
+    int32_t code_point;
+    CBU8_NEXT(src, i, src_len, code_point);
+
+    if (!IsValidCodepoint(code_point)) {
+      success = false;
+      code_point = kErrorCodePoint;
+    }
+
+    UnicodeAppendUnsafe(dest, dest_len, code_point);
+  }
+
+  return success;
+}
+
+template <typename DestChar>
+bool DoUTFConversion(const char16* src,
+                     int32_t src_len,
+                     DestChar* dest,
+                     int32_t* dest_len) {
+  bool success = true;
+
+  auto ConvertSingleChar = [&success](char16 in) -> int32_t {
+    if (!CBU16_IS_SINGLE(in) || !IsValidCodepoint(in)) {
+      success = false;
+      return kErrorCodePoint;
+    }
+    return in;
+  };
+
+  int32_t i = 0;
+
+  // Always have another symbol in order to avoid checking boundaries in the
+  // middle of the surrogate pair.
+  while (i < src_len - 1) {
+    int32_t code_point;
+
+    if (CBU16_IS_LEAD(src[i]) && CBU16_IS_TRAIL(src[i + 1])) {
+      code_point = CBU16_GET_SUPPLEMENTARY(src[i], src[i + 1]);
+      if (!IsValidCodepoint(code_point)) {
+        code_point = kErrorCodePoint;
+        success = false;
+      }
+      i += 2;
+    } else {
+      code_point = ConvertSingleChar(src[i]);
+      ++i;
+    }
+
+    UnicodeAppendUnsafe(dest, dest_len, code_point);
+  }
+
+  if (i < src_len)
+    UnicodeAppendUnsafe(dest, dest_len, ConvertSingleChar(src[i]));
+
+  return success;
+}
+
+#if defined(WCHAR_T_IS_UTF32)
+
+template <typename DestChar>
+bool DoUTFConversion(const wchar_t* src,
+                     int32_t src_len,
+                     DestChar* dest,
+                     int32_t* dest_len) {
+  bool success = true;
+
+  for (int32_t i = 0; i < src_len; ++i) {
+    int32_t code_point = src[i];
+
+    if (!IsValidCodepoint(code_point)) {
+      success = false;
+      code_point = kErrorCodePoint;
+    }
+
+    UnicodeAppendUnsafe(dest, dest_len, code_point);
+  }
+
+  return success;
+}
+
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+// UTFConversion --------------------------------------------------------------
+// Function template for generating all UTF conversions.
+
+template <typename InputString, typename DestString>
+bool UTFConversion(const InputString& src_str, DestString* dest_str) {
+  if (IsStringASCII(src_str)) {
+    dest_str->assign(src_str.begin(), src_str.end());
+    return true;
+  }
+
+  dest_str->resize(src_str.length() *
+                   size_coefficient_v<typename InputString::value_type,
+                                      typename DestString::value_type>);
+
+  // Empty string is ASCII => it OK to call operator[].
+  auto* dest = &(*dest_str)[0];
+
+  // ICU requires 32 bit numbers.
+  int32_t src_len32 = static_cast<int32_t>(src_str.length());
+  int32_t dest_len32 = 0;
+
+  bool res = DoUTFConversion(src_str.data(), src_len32, dest, &dest_len32);
+
+  dest_str->resize(dest_len32);
+  dest_str->shrink_to_fit();
+
+  return res;
+}
+
+}  // namespace
+
+// UTF16 <-> UTF8 --------------------------------------------------------------
+
+bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
+  return UTFConversion(StringPiece(src, src_len), output);
+}
+
+string16 UTF8ToUTF16(StringPiece utf8) {
+  string16 ret;
+  // Ignore the success flag of this call, it will do the best it can for
+  // invalid input, which is what we want here.
+  UTF8ToUTF16(utf8.data(), utf8.size(), &ret);
+  return ret;
+}
+
+bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
+  return UTFConversion(StringPiece16(src, src_len), output);
+}
+
+std::string UTF16ToUTF8(StringPiece16 utf16) {
+  std::string ret;
+  // Ignore the success flag of this call, it will do the best it can for
+  // invalid input, which is what we want here.
+  UTF16ToUTF8(utf16.data(), utf16.length(), &ret);
+  return ret;
+}
+
+// UTF-16 <-> Wide -------------------------------------------------------------
+
+#if defined(WCHAR_T_IS_UTF16)
+// When wide == UTF-16 the conversions are a NOP.
+
+bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
+  output->assign(src, src + src_len);
+  return true;
+}
+
+string16 WideToUTF16(WStringPiece wide) {
+  return string16(wide.begin(), wide.end());
+}
+
+bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
+  output->assign(src, src + src_len);
+  return true;
+}
+
+std::wstring UTF16ToWide(StringPiece16 utf16) {
+  return std::wstring(utf16.begin(), utf16.end());
+}
+
+#elif defined(WCHAR_T_IS_UTF32)
+
+bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
+  return UTFConversion(base::WStringPiece(src, src_len), output);
+}
+
+string16 WideToUTF16(WStringPiece wide) {
+  string16 ret;
+  // Ignore the success flag of this call, it will do the best it can for
+  // invalid input, which is what we want here.
+  WideToUTF16(wide.data(), wide.length(), &ret);
+  return ret;
+}
+
+bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
+  return UTFConversion(StringPiece16(src, src_len), output);
+}
+
+std::wstring UTF16ToWide(StringPiece16 utf16) {
+  std::wstring ret;
+  // Ignore the success flag of this call, it will do the best it can for
+  // invalid input, which is what we want here.
+  UTF16ToWide(utf16.data(), utf16.length(), &ret);
+  return ret;
+}
+
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+// UTF-8 <-> Wide --------------------------------------------------------------
+
+// UTF8ToWide is the same code, regardless of whether wide is 16 or 32 bits
+
+bool UTF8ToWide(const char* src, size_t src_len, std::wstring* output) {
+  return UTFConversion(StringPiece(src, src_len), output);
+}
+
+std::wstring UTF8ToWide(StringPiece utf8) {
+  std::wstring ret;
+  // Ignore the success flag of this call, it will do the best it can for
+  // invalid input, which is what we want here.
+  UTF8ToWide(utf8.data(), utf8.length(), &ret);
+  return ret;
+}
+
+#if defined(WCHAR_T_IS_UTF16)
+// Easy case since we can use the "utf" versions we already wrote above.
+
+bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
+  return UTF16ToUTF8(as_u16cstr(src), src_len, output);
+}
+
+std::string WideToUTF8(WStringPiece wide) {
+  return UTF16ToUTF8(StringPiece16(as_u16cstr(wide), wide.size()));
+}
+
+#elif defined(WCHAR_T_IS_UTF32)
+
+bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
+  return UTFConversion(WStringPiece(src, src_len), output);
+}
+
+std::string WideToUTF8(WStringPiece wide) {
+  std::string ret;
+  // Ignore the success flag of this call, it will do the best it can for
+  // invalid input, which is what we want here.
+  WideToUTF8(wide.data(), wide.length(), &ret);
+  return ret;
+}
+
+#endif  // defined(WCHAR_T_IS_UTF32)
+
+string16 ASCIIToUTF16(StringPiece ascii) {
+  DCHECK(IsStringASCII(ascii)) << ascii;
+  return string16(ascii.begin(), ascii.end());
+}
+
+std::string UTF16ToASCII(StringPiece16 utf16) {
+  DCHECK(IsStringASCII(utf16)) << UTF16ToUTF8(utf16);
+  return std::string(utf16.begin(), utf16.end());
+}
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/strings/utf_string_conversions.h b/security/sandbox/chromium/base/strings/utf_string_conversions.h
new file mode 100644
index 0000000000..f780fb4f4f
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/utf_string_conversions.h
@@ -0,0 +1,54 @@
+// 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_STRINGS_UTF_STRING_CONVERSIONS_H_
+#define BASE_STRINGS_UTF_STRING_CONVERSIONS_H_
+
+#include <stddef.h>
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
+
+namespace base {
+
+// These convert between UTF-8, -16, and -32 strings. They are potentially slow,
+// so avoid unnecessary conversions. The low-level versions return a boolean
+// indicating whether the conversion was 100% valid. In this case, it will still
+// do the best it can and put the result in the output buffer. The versions that
+// return strings ignore this error and just return the best conversion
+// possible.
+BASE_EXPORT bool WideToUTF8(const wchar_t* src, size_t src_len,
+                            std::string* output);
+BASE_EXPORT std::string WideToUTF8(WStringPiece wide) WARN_UNUSED_RESULT;
+BASE_EXPORT bool UTF8ToWide(const char* src, size_t src_len,
+                            std::wstring* output);
+BASE_EXPORT std::wstring UTF8ToWide(StringPiece utf8) WARN_UNUSED_RESULT;
+
+BASE_EXPORT bool WideToUTF16(const wchar_t* src, size_t src_len,
+                             string16* output);
+BASE_EXPORT string16 WideToUTF16(WStringPiece wide) WARN_UNUSED_RESULT;
+BASE_EXPORT bool UTF16ToWide(const char16* src, size_t src_len,
+                             std::wstring* output);
+BASE_EXPORT std::wstring UTF16ToWide(StringPiece16 utf16) WARN_UNUSED_RESULT;
+
+BASE_EXPORT bool UTF8ToUTF16(const char* src, size_t src_len, string16* output);
+BASE_EXPORT string16 UTF8ToUTF16(StringPiece utf8) WARN_UNUSED_RESULT;
+BASE_EXPORT bool UTF16ToUTF8(const char16* src, size_t src_len,
+                             std::string* output);
+BASE_EXPORT std::string UTF16ToUTF8(StringPiece16 utf16) WARN_UNUSED_RESULT;
+
+// This converts an ASCII string, typically a hardcoded constant, to a UTF16
+// string.
+BASE_EXPORT string16 ASCIIToUTF16(StringPiece ascii) WARN_UNUSED_RESULT;
+
+// Converts to 7-bit ASCII by truncating. The result must be known to be ASCII
+// beforehand.
+BASE_EXPORT std::string UTF16ToASCII(StringPiece16 utf16) WARN_UNUSED_RESULT;
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_UTF_STRING_CONVERSIONS_H_