Re-committing http://codereview.chromium.org/6803005/ after fixing multi-dll build:

third_party/libphonenumber/cpp/src/stringutil.h

+// Copyright (C) 2011 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Author: Philippe Liard
+
+#ifndef I18N_PHONENUMBERS_STRINGUTIL_H_
+#define I18N_PHONENUMBERS_STRINGUTIL_H_
+
+#include <cstddef>
+#include <string>
+
+#include "base/basictypes.h"
+
+namespace i18n {
+namespace phonenumbers {
+
+using std::string;
+
+// Supports string("hello") + 10.
+string operator+(const string& s, int n);
+
+// Converts integer to string.
+string SimpleItoa(uint64 n);
+string SimpleItoa(int n);
+
+// Replaces any occurrence of the character 'remove' (or the characters
+// in 'remove') with the character 'replacewith'.
+void StripString(string* s, const char* remove, char replacewith);
+
+// Returns true if 'in' starts with 'prefix' and writes 'in' minus 'prefix' into
+// 'out'.
+bool TryStripPrefixString(const string& in, const string& prefix, string* out);
+
+// Returns true if 's' ends with 'suffix'.
+bool HasSuffixString(const string& s, const string& suffix);
+
+// Converts string to int32.
+void safe_strto32(const string& s, int32 *n);
+
+// Converts string to uint64.
+void safe_strtou64(const string& s, uint64 *n);
+
+// Remove all occurrences of a given set of characters from a string.
+void strrmm(string* s, const string& chars);
+
+// Holds a reference to a std::string or C string. It can also be constructed
+// from an integer which is converted to a string.
+class StringHolder {
+public:
+  // Don't make the constructors explicit to make the StrCat usage convenient.
+  StringHolder(const string& s);
+  StringHolder(const char* s);
+  StringHolder(uint64 n);
+  ~StringHolder();
+
+  const string* GetString() const {
+    return string_;
+  }
+
+  const char* GetCString() const {
+    return cstring_;
+  }
+
+  size_t Length() const {
+    return len_;
+  }
+
+private:
+  const string converted_string_;  // Stores the string converted from integer.
+  const string* const string_;
+  const char* const cstring_;
+  const size_t len_;
+};
+
+string& operator+=(string& lhs, const StringHolder& rhs);
+
+// Efficient string concatenation.
+
+string StrCat(const StringHolder& s1, const StringHolder& s2);
+
+string StrCat(const StringHolder& s1, const StringHolder& s2,
+              const StringHolder& s3);
+
+string StrCat(const StringHolder& s1, const StringHolder& s2,
+              const StringHolder& s3, const StringHolder& s4);
+
+string StrCat(const StringHolder& s1, const StringHolder& s2,
+              const StringHolder& s3, const StringHolder& s4,
+              const StringHolder& s5);
+
+string StrCat(const StringHolder& s1, const StringHolder& s2,
+              const StringHolder& s3, const StringHolder& s4,
+              const StringHolder& s5, const StringHolder& s6);
+
+string StrCat(const StringHolder& s1, const StringHolder& s2,
+              const StringHolder& s3, const StringHolder& s4,
+              const StringHolder& s5, const StringHolder& s6,
+              const StringHolder& s7);
+
+string StrCat(const StringHolder& s1, const StringHolder& s2,
+              const StringHolder& s3, const StringHolder& s4,
+              const StringHolder& s5, const StringHolder& s6,
+              const StringHolder& s7, const StringHolder& s8,
+              const StringHolder& s9, const StringHolder& s10,
+              const StringHolder& s11);
+
+void StrAppend(string* dest, const StringHolder& s1);
+
+void StrAppend(string* dest, const StringHolder& s1, const StringHolder& s2);
+
+}  // namespace phonenumbers
+}  // namespace i18n
+
+#endif  // I18N_PHONENUMBERS_STRINGUTIL_H_