[debugger] infrastructure for side-effect-free debug-evaluate.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index 6503041b9215e4d70a04d87059c0da92eaba2d07..bbf1f22443d9402f72e6102b7bfdf497b3760726 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -1570,6 +1570,10 @@ ExternalReference ExternalReference::debug_is_active_address(
   return ExternalReference(isolate->debug()->is_active_address());
 }
 
+ExternalReference ExternalReference::debug_hook_on_function_call_address(
+    Isolate* isolate) {
+  return ExternalReference(isolate->debug()->hook_on_function_call_address());
+}
 
 ExternalReference ExternalReference::debug_after_break_target_address(
     Isolate* isolate) {