Rewrite double.parse.

runtime/lib/string_patch.dart

Index: runtime/lib/string_patch.dart
diff --git a/runtime/lib/string_patch.dart b/runtime/lib/string_patch.dart
index e9f575940db25bc174bee17c4c43497df754ad20..8d54046cda1d4c597c2e3d33b32a5e668e3d43d8 100644
--- a/runtime/lib/string_patch.dart
+++ b/runtime/lib/string_patch.dart
@@ -516,7 +516,8 @@ class _OneByteString extends _StringBase implements String {
   bool _isWhitespace(int codePoint) {
     return
       (codePoint == 32) || // Space.
-      ((9 <= codePoint) && (codePoint <= 13)); // CR, LF, TAB, etc.
+      ((9 <= codePoint) && (codePoint <= 13)) ||  // CR, LF, TAB, etc.
+      (codePoint == 0xA0);  // NBSP.
   }
 
   String _substringUncheckedNative(int startIndex, int endIndex)
@@ -574,7 +575,8 @@ class _TwoByteString extends _StringBase implements String {
   bool _isWhitespace(int codePoint) {
     return
       (codePoint == 32) || // Space.
-      ((9 <= codePoint) && (codePoint <= 13)); // CR, LF, TAB, etc.
+      ((9 <= codePoint) && (codePoint <= 13)) || // CR, LF, TAB, etc.
+      (codePoint == 0xA0);  // NBSP.
   }
 }