Reapply "Per-closure breakpoints; restructure breakpoint implementation to keep a list of condition…

runtime/observatory/lib/src/service/object.dart

Index: runtime/observatory/lib/src/service/object.dart
diff --git a/runtime/observatory/lib/src/service/object.dart b/runtime/observatory/lib/src/service/object.dart
index 8e1a496cc50f26ede618078f99fc0783e159e128..e9ecdee1ee11eb204969663d15a4f0a2de64b031 100644
--- a/runtime/observatory/lib/src/service/object.dart
+++ b/runtime/observatory/lib/src/service/object.dart
@@ -1206,6 +1206,11 @@ class Isolate extends ServiceObjectOwner with Coverage {
                      { 'functionId': function.id });
   }
 
+  Future<ServiceObject> addBreakOnActivation(Instance closure) {
+    return invokeRpc('_addBreakpointAtActivation',
+                     { 'objectId': closure.id });
+  }
+
   Future removeBreakpoint(Breakpoint bpt) {
     return invokeRpc('removeBreakpoint',
                      { 'breakpointId': bpt.id });