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

third_party/libphonenumber/cpp/src/utf/unilib.cc

+/**
+ * Copyright 2010 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: Shawn Ligocki
+
+#include "utf/unilib.h"
+
+#include "base/basictypes.h"
+#include "utf/utf.h"
+
+namespace UniLib {
+
+namespace {
+
+// MOE: start_strip
+// MOE: end_strip
+// Codepoints not allowed for interchange are:
+//   C0 (ASCII) controls: U+0000 to U+001F excluding Space (SP, U+0020),
+//       Horizontal Tab (HT, U+0009), Line-Feed (LF, U+000A),
+//       Form Feed (FF, U+000C) and Carriage-Return (CR, U+000D)
+//   C1 controls: U+007F to U+009F
+//   Surrogates: U+D800 to U+DFFF
+//   Non-characters: U+FDD0 to U+FDEF and U+xxFFFE to U+xxFFFF for all xx
+inline bool IsInterchangeValidCodepoint(char32 c) {
+  return !((c >= 0x00 && c <= 0x08) || c == 0x0B || (c >= 0x0E && c <= 0x1F) ||
+           (c >= 0x7F && c <= 0x9F) ||
+           (c >= 0xD800 && c <= 0xDFFF) ||
+           (c >= 0xFDD0 && c <= 0xFDEF) || (c&0xFFFE) == 0xFFFE);
+}
+
+}  // namespace
+
+int SpanInterchangeValid(const char* begin, int byte_length) {
+  char32 rune;
+  const char* p = begin;
+  const char* end = begin + byte_length;
+  while (p < end) {
+    int bytes_consumed = charntorune(&rune, p, end - p);
+    // We want to accept Runeerror == U+FFFD as a valid char, but it is used
+    // by chartorune to indicate error. Luckily, the real codepoint is size 3
+    // while errors return bytes_consumed == 1.
+    if ((rune == Runeerror && bytes_consumed == 1) ||
+        !IsInterchangeValidCodepoint(rune)) {
+      break;  // Found
+    }
+    p += bytes_consumed;
+  }
+  return p - begin;
+}
+
+}  // namespace UniLib