Merge bleeding edge into the GC branch up to 7948. The asserts

src/extensions/experimental/language-matcher.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 231 matching lines @@
   }
 
   // Convert ICU locale name into BCP47 format.
   UErrorCode status = U_ZERO_ERROR;
   uloc_toLanguageTag(result->icu_id, result->bcp47_id,
                      ULOC_FULLNAME_CAPACITY, false, &status);
   return !U_FAILURE(status);
 }
 
 } }  // namespace v8::internal