Precompilation:

runtime/vm/precompiler.cc

Index: runtime/vm/precompiler.cc
diff --git a/runtime/vm/precompiler.cc b/runtime/vm/precompiler.cc
index 93d2107ed701f00bce7771e971705980d2b624f7..97f90c321d8e1cd1b3b90932ad52994e6ec71394 100644
--- a/runtime/vm/precompiler.cc
+++ b/runtime/vm/precompiler.cc
@@ -229,7 +229,6 @@ void Precompiler::AddRoots(Dart_QualifiedFunctionName embedder_entry_points[]) {
     { "dart:core", "AbstractClassInstantiationError",
                    "AbstractClassInstantiationError._create" },
     { "dart:core", "ArgumentError", "ArgumentError." },
-    { "dart:core", "AssertionError", "AssertionError." },
     { "dart:core", "CyclicInitializationError",
                    "CyclicInitializationError." },
     { "dart:core", "FallThroughError", "FallThroughError._create" },
@@ -241,6 +240,7 @@ void Precompiler::AddRoots(Dart_QualifiedFunctionName embedder_entry_points[]) {
     { "dart:core", "RangeError", "RangeError.range" },
     { "dart:core", "StackOverflowError", "StackOverflowError." },
     { "dart:core", "UnsupportedError", "UnsupportedError." },
+    { "dart:core", "_AssertionError", "_AssertionError._create" },
     { "dart:core", "_CastError", "_CastError._create" },
     { "dart:core", "_InternalError", "_InternalError." },
     { "dart:core", "_InvocationMirror", "_allocateInvocationMirror" },