Per-closure breakpoints; restructure breakpoint implementation to keep a list of conditions.

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 98a128b06ed86ea9a92b296de83aa854877c4fc4..c515401e16080ab493e0e183fef00423b1867268 100644
--- a/runtime/observatory/lib/src/service/object.dart
+++ b/runtime/observatory/lib/src/service/object.dart
@@ -1172,6 +1172,11 @@ 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 });