Add basic support for Latin1 to the API.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index f01af258bcd13cef73ac88e6cf1b14dda8f71d82..76343237ba39c9c6977c44adb219f7352de415a4 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -676,10 +676,18 @@ class Heap {
       PretenureFlag pretenure = NOT_TENURED);
   MUST_USE_RESULT inline MaybeObject* AllocateStringFromUtf8(
       Vector<const char> str,
-      PretenureFlag pretenure = NOT_TENURED);
+      PretenureFlag pretenure = NOT_TENURED,
+      String::AsciiHint ascii_hint = String::MAYBE_ASCII);
   MUST_USE_RESULT MaybeObject* AllocateStringFromUtf8Slow(
       Vector<const char> str,
       PretenureFlag pretenure = NOT_TENURED);
+  MUST_USE_RESULT inline MaybeObject* AllocateStringFromLatin1(
+      Vector<const char> str,
+      PretenureFlag pretenure = NOT_TENURED,
+      String::AsciiHint ascii_hint = String::MAYBE_ASCII);
+  MUST_USE_RESULT MaybeObject* AllocateStringFromLatin1Slow(
+      Vector<const char> str,
+      PretenureFlag pretenure = NOT_TENURED);
   MUST_USE_RESULT MaybeObject* AllocateStringFromTwoByte(
       Vector<const uc16> str,
       PretenureFlag pretenure = NOT_TENURED);