Add optional message argument to assert statements in the VM.

runtime/vm/code_generator.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 567 matching lines @@
 // Throw assertion error if the object is null. (cf. Boolean Conversion
 // in language Spec.)
 // Arg0: bad object.
 // Return value: none, throws TypeError or AssertionError.
 DEFINE_RUNTIME_ENTRY(NonBoolTypeError, 1) {
   const TokenPosition location = GetCallerLocation();
   const Instance& src_instance =
       Instance::CheckedHandle(zone, arguments.ArgAt(0));
 
   if (src_instance.IsNull()) {
-    const Array& args = Array::Handle(zone, Array::New(4));
+    const Array& args = Array::Handle(zone, Array::New(5));
     args.SetAt(
         0, String::Handle(
                zone,
                String::New(
                    "Failed assertion: boolean expression must not be null")));
 
     // No source code for this assertion, set url to null.
     args.SetAt(1, String::Handle(zone, String::null()));
     args.SetAt(2, Smi::Handle(zone, Smi::New(0)));
     args.SetAt(3, Smi::Handle(zone, Smi::New(0)));
+    args.SetAt(4, String::Handle(zone, String::null()));
 
     Exceptions::ThrowByType(Exceptions::kAssertion, args);
     UNREACHABLE();
   }
 
   ASSERT(!src_instance.IsBool());
   const Type& bool_interface = Type::Handle(Type::BoolType());
   const AbstractType& src_type =
       AbstractType::Handle(zone, src_instance.GetType(Heap::kNew));
   const String& no_bound_error = String::Handle(zone);
@@ skipping 1682 matching lines @@
   const intptr_t elm_size = old_data.ElementSizeInBytes();
   const TypedData& new_data =
       TypedData::Handle(TypedData::New(cid, new_size, Heap::kOld));
   TypedData::Copy(new_data, 0, old_data, 0, old_size * elm_size);
   typed_data_cell.SetAt(0, new_data);
   arguments.SetReturn(new_data);
 }
 
 
 }  // namespace dart