Reland: Debugger: deduplicate shared function info when setting script break points.

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index e802ea6975383562edb28cf3754d23e3c733da0f..7dcf1b403f3ecf51b5cb23a92a1331e366f52ff7 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -2646,6 +2646,15 @@ RUNTIME_FUNCTION(Runtime_ExecuteInDebugContext) {
 }
 
 
+RUNTIME_FUNCTION(Runtime_GetDebugContext) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 0);
+  Handle<Context> context = isolate->debug()->GetDebugContext();
+  context->set_security_token(isolate->native_context()->security_token());
+  return context->global_proxy();
+}
+
+
 // Performs a GC.
 // Presently, it only does a full GC.
 RUNTIME_FUNCTION(Runtime_CollectGarbage) {