Add support for javascript incompatibility warnings.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 35921)
+++ runtime/vm/object.cc	(working copy)
@@ -700,9 +700,13 @@
 
   String& error_str = String::Handle();
   error_str = String::New("SnapshotWriter Error", Heap::kOld);
-  *snapshot_writer_error_ = LanguageError::New(error_str, Heap::kOld);
+  *snapshot_writer_error_ = LanguageError::New(error_str,
+                                               LanguageError::kError,
+                                               Heap::kOld);
   error_str = String::New("Branch offset overflow", Heap::kOld);
-  *branch_offset_error_ = LanguageError::New(error_str, Heap::kOld);
+  *branch_offset_error_ = LanguageError::New(error_str,
+                                             LanguageError::kBailout,
+                                             Heap::kOld);
 
   ASSERT(!null_object_->IsSmi());
   ASSERT(!null_array_->IsSmi());
@@ -12384,6 +12388,7 @@
 
 
 RawLanguageError* LanguageError::New(const String& formatted_message,
+                                     Kind kind,
                                      Heap::Space space) {
   ASSERT(Object::language_error_class() != Class::null());
   LanguageError& result = LanguageError::Handle();
@@ -12395,6 +12400,7 @@
     result ^= raw;
   }
   result.set_formatted_message(formatted_message);
+  result.set_kind(kind);
   return result.raw();
 }
 
@@ -12440,6 +12446,7 @@
     case kError: message_header = "error"; break;
     case kMalformedType: message_header = "malformed type"; break;
     case kMalboundedType: message_header = "malbounded type"; break;
+    case kBailout: message_header = "bailout"; break;
     default: message_header = ""; UNREACHABLE();
   }
   String& result = String::Handle();