Add StringToSizeT to base/string_number_conversions.

base/string_number_conversions.h

Index: base/string_number_conversions.h
diff --git a/base/string_number_conversions.h b/base/string_number_conversions.h
index b002faa341ab57f6ba36b4e59c6c18310a26cd37..54f05b0954327dfdc2c91404a77b7973b079f58c 100644
--- a/base/string_number_conversions.h
+++ b/base/string_number_conversions.h
@@ -71,6 +71,9 @@ BASE_EXPORT bool StringToInt64(const StringPiece16& input, int64* output);
 BASE_EXPORT bool StringToUint64(const StringPiece& input, uint64* output);
 BASE_EXPORT bool StringToUint64(const StringPiece16& input, uint64* output);
 
+BASE_EXPORT bool StringToSizeT(const StringPiece& input, size_t* output);
+BASE_EXPORT bool StringToSizeT(const 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-fininte values (such as