Made Date parser work on flat strings instead of arbitrary ones.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 134fddf114d0f22dab922198cbb6b4d5c94b8015..940c89d6c76f6e86e8b8a4a6ccd72cf02c9c741d 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -4484,8 +4484,19 @@ static Object* Runtime_DateParseString(Arguments args) {
   CONVERT_CHECKED(String, string_object, args[0]);
 
   Handle<String> str(string_object);
+  FlattenString(str);
   Handle<FixedArray> output = Factory::NewFixedArray(DateParser::OUTPUT_SIZE);
-  if (DateParser::Parse(*str, *output)) {
+  bool result;
+  {
+    AssertNoAllocation no_allocation;
+    if (StringShape(*str).IsAsciiRepresentation()) {
+      result = DateParser::Parse(str->ToAsciiVector(), *output);
+    } else {
+      ASSERT(StringShape(*str).IsTwoByteRepresentation());
+      result = DateParser::Parse(str->ToUC16Vector(), *output);
+    }
+  }
+  if (result) {
     return *Factory::NewJSArrayWithElements(output);
   } else {
     return *Factory::null_value();