Add basic support for Latin1 strings to the API.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 4b91ca43cee17984d9ffa9c4d5cf6664ce4b11f8..544926418d353cbd962f6e3524987d85b22b4c8e 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -675,10 +675,18 @@ 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);