Move dart:web to pkg:htmlescape.

runtime/bin/builtin_nolib.cc

Index: runtime/bin/builtin_nolib.cc
diff --git a/runtime/bin/builtin_nolib.cc b/runtime/bin/builtin_nolib.cc
index 91c3ce384035af3407c89077ef6ff36ba6abc62e..58f813329648fb0d5400bb48e5be801d2ba3a1e2 100644
--- a/runtime/bin/builtin_nolib.cc
+++ b/runtime/bin/builtin_nolib.cc
@@ -17,16 +17,14 @@ Builtin::builtin_lib_props Builtin::builtin_libraries_[] = {
   { DartUtils::kUriLibURL,     NULL,            false },
   { DartUtils::kCryptoLibURL,  NULL,            false },
   { DartUtils::kIOLibURL,      NULL,            true  },
-  { DartUtils::kUtfLibURL,     NULL,            false },
-  { DartUtils::kWebLibURL,     web_source_,     false }
+  { DartUtils::kUtfLibURL,     NULL,            false }
 };
 
 
 Dart_Handle Builtin::Source(BuiltinLibraryId id) {
   ASSERT((sizeof(builtin_libraries_) / sizeof(builtin_lib_props)) ==
          kInvalidLibrary);
-  ASSERT(id == kWebLibrary);
-  return Dart_NewString(builtin_libraries_[id].source_);
+  return Dart_NewApiError("Unreachable code in Builtin::Source (%d).", id);
 }