Add basic support for Latin1 to the API.

src/heap-inl.h

Index: src/heap-inl.h
diff --git a/src/heap-inl.h b/src/heap-inl.h
index 4a827fef176fd57cafb2c929bb834cd229737aaa..1bc6e8db5aa141f9fa11b9510c2c3403a102a347 100644
--- a/src/heap-inl.h
+++ b/src/heap-inl.h
@@ -83,9 +83,14 @@ void PromotionQueue::ActivateGuardIfOnTheSamePage() {
 
 
 MaybeObject* Heap::AllocateStringFromUtf8(Vector<const char> str,
-                                          PretenureFlag pretenure) {
-  // Check for ASCII first since this is the common case.
-  if (String::IsAscii(str.start(), str.length())) {
+                                          PretenureFlag pretenure,
+                                          String::AsciiHint ascii_hint) {
+  if ((ascii_hint == String::MAYBE_ASCII &&
+       String::IsAscii(str.start(), str.length())) ||
+      ascii_hint == String::ASCII) {
+    // Assert that the ASCII-hint is correct.
+    ASSERT(ascii_hint != String::ASCII ||
+           String::IsAscii(str.start(), str.length()));
     // If the string is ASCII, we do not need to convert the characters
     // since UTF8 is backwards compatible with ASCII.
     return AllocateStringFromAscii(str, pretenure);
@@ -95,6 +100,24 @@ MaybeObject* Heap::AllocateStringFromUtf8(Vector<const char> str,
 }
 
 
+MaybeObject* Heap::AllocateStringFromLatin1(Vector<const char> str,
+                                            PretenureFlag pretenure,
+                                            String::AsciiHint ascii_hint) {
+  if ((ascii_hint == String::MAYBE_ASCII &&
+        String::IsAscii(str.start(), str.length())) ||
+       ascii_hint == String::ASCII) {
+     // Assert that the strict ASCII-hint is correct.
+     ASSERT(ascii_hint != String::ASCII ||
+            String::IsAscii(str.start(), str.length()));
+     // If the string is ASCII, we do not need to convert the characters
+     // since Latin1 is backwards compatible with ASCII.
+     return AllocateStringFromAscii(str, pretenure);
+  }
+  // Non-ASCII and we need to decode.
+  return AllocateStringFromLatin1Slow(str, pretenure);
+}
+
+
 MaybeObject* Heap::AllocateSymbol(Vector<const char> str,
                                   int chars,
                                   uint32_t hash_field) {