Move negative length checks from Dart into the native.

runtime/lib/typed_data.cc

Index: runtime/lib/typed_data.cc
===================================================================
--- runtime/lib/typed_data.cc	(revision 22079)
+++ runtime/lib/typed_data.cc	(working copy)
@@ -42,7 +42,6 @@
 
 // Checks to see if a length will not result in an OOM error.
 static void LengthCheck(intptr_t len, intptr_t max) {
-  ASSERT(len >= 0);
   if (len > max) {
     const String& error = String::Handle(String::NewFormatted(
         "insufficient memory to allocate a TypedData object of length (%"Pd")",
@@ -50,6 +49,12 @@
     const Array& args = Array::Handle(Array::New(1));
     args.SetAt(0, error);
     Exceptions::ThrowByType(Exceptions::kOutOfMemory, args);
+  } else if (len < 0) {
+    const String& error = String::Handle(String::NewFormatted(
+        "%"Pd" must be greater than 0", len));
+    const Array& args = Array::Handle(Array::New(1));
+    args.SetAt(0, error);
+    Exceptions::ThrowByType(Exceptions::kArgument, args);
   }
 }