Debugger: load debugger builtins as normal native JS.

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index 529c659e181d8f35cca3e05909d8e3a76fa9a3b4..66d64f06696e6eef6f049d50e2fdc53b1f6d088d 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -91,6 +91,7 @@ class CallSite {
   /* Error */                                                                  \
   T(None, "")                                                                  \
   T(CyclicProto, "Cyclic __proto__ value")                                     \
+  T(Debugger, "Debugger: %")                                                   \
   T(DebuggerLoading, "Error loading debugger")                                 \
   T(DefaultOptionsMissing, "Internal % error. Default options are missing.")   \
   T(UncaughtException, "Uncaught %")                                           \
@@ -119,6 +120,8 @@ class CallSite {
   T(DataViewNotArrayBuffer,                                                    \
     "First argument to DataView constructor must be an ArrayBuffer")           \
   T(DateType, "this is not a Date object.")                                    \
+  T(DebuggerFrame, "Debugger: Invalid frame index.")                           \
+  T(DebuggerType, "Debugger: Parameters have wrong types.")                    \
   T(DefineDisallowed, "Cannot define property:%, object is not extensible.")   \
   T(DuplicateTemplateProperty, "Object template has duplicate property '%'")   \
   T(ExtendsValueGenerator,                                                     \