Make dart2js String.split match the VM version.

sdk/lib/core/string.dart

Index: sdk/lib/core/string.dart
diff --git a/sdk/lib/core/string.dart b/sdk/lib/core/string.dart
index 90e6b508b6b14eacbb5985033be2aa3814879207..8366764cab00681c103685058e6069f499e57d05 100644
--- a/sdk/lib/core/string.dart
+++ b/sdk/lib/core/string.dart
@@ -463,11 +463,30 @@ abstract class String implements Comparable<String>, Pattern {
   String replaceAllMapped(Pattern from, String replace(Match match));
 
   /**
-   * Splits the string at matches of [pattern]. Returns
-   * a list of substrings.
+   * Splits the string at matches of [pattern] and returns a list of substrings.
    *
-   * Splitting with an empty string pattern (`''`) splits at UTF-16 code unit
-   * boundaries and not at rune boundaries:
+   * Finds all the matches of `pattern` in this string,
+   * and returns the list of the substrings between the matches.
+   *
+   *     var string = "Hello world!";
+   *     string.split(" ");                      // ['Hello', 'world!'];
+   *
+   * Empty matches at the beginning and end of the strings are ignored,
+   * and so are empty matches right after another match.
+   *
+   *     var string = "abba";
+   *     string.split(new RegExp(r"b*"));        // ['a', 'a']
+   *                                             // not ['', 'a', 'a', '']
+   *
+   * If this string is empty, the result is an empty list if `pattern` matches
+   * the empty string, and it is `[""]` if the pattern doesn't match.
+   *
+   *     var string = '';
+   *     string.split('');                       // []
+   *     string.split("a");                      // ['']
+   *
+   * Splitting happends at UTF-16 code unit boundaries,

[Søren Gjesse, 2014/10/27 08:35:04]

Add 'NOTE:'

[Lasse Reichstein Nielsen, 2014/10/28 10:15:04]

I try to avoid writing "NOTE" or "NOTICE" unless something is surprisingly
broken. The fact that it is written at all should be enough.
There is no "d" in "happens", though.

Dart 2.0: Remove the word "rune". 

+   * and not at rune boundaries:
    *
    *     var string = 'Pub';
    *     string.split('');                       // ['P', 'u', 'b']
@@ -480,11 +499,11 @@ abstract class String implements Comparable<String>, Pattern {
    *     string = '\u{1D11E}';
    *     string.split('').length;                 // 2
    *
-   * You should [map] the runes unless you are certain that the string is in
-   * the basic multilingual plane (meaning that each code unit represents a
-   * rune):
+   * To get a list of strings containing the individual runes of a string,
+   * you should not use split. You can instead map each rune to a string
+   * as follows:
    *
-   *     string.runes.map((rune) => new String.fromCharCode(rune));
+   *     string.runes.map((rune) => new String.fromCharCode(rune)).toList();
    */
   List<String> split(Pattern pattern);