Localize variable parts in form validation messages.

Some form validation messages contain limit information or current value
length.  They are numbers or date/time, and we should localize them.

For rangeOverflow/rangeUnderflow:
We just apply localizeValue()

For tooLong:
We can't use localizeValue() because localizeValue() for text input types
does nothing. We add a function to Locale class, and it handles localization
of numbers.

Also, we remove some functions in LocalizedStrings.

BUG=161733
TEST=automated

Review URL: https://chromiumcodereview.appspot.com/23480099

git-svn-id: svn://svn.chromium.org/blink/trunk@158072 bbb929c8-8fbe-4397-9dbb-9b2b20218538