Add a safe API for creating ASCII-only strings

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 0c3460efb4318a17de2956f7972d5d2ddb4bd61f..8e7ba6639799d16769350e0b3cbbb6f97bb84797 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -4849,6 +4849,20 @@ Local<String> v8::String::New(const char* data, int length) {
 }
 
 
+Local<String> v8::String::NewFromAscii(const char* data, int length) {
+  i::Isolate* isolate = i::Isolate::Current();
+  EnsureInitializedForIsolate(isolate, "v8::String::NewFromAscii()");
+  LOG_API(isolate, "String::NewFromAscii(char)");
+  if (length == 0) return Empty();
+  ENTER_V8(isolate);
+  if (length == -1) length = i::StrLength(data);
+  i::Handle<i::String> result =
+      isolate->factory()->NewStringFromAsciiSafe(
+          i::Vector<const char>(data, length));
+  return Utils::ToLocal(result);
+}
+
+
 Local<String> v8::String::Concat(Handle<String> left, Handle<String> right) {
   i::Handle<i::String> left_string = Utils::OpenHandle(*left);
   i::Isolate* isolate = left_string->GetIsolate();