Add function for one-time stop at function entry

runtime/vm/debugger_api_impl.cc

Index: runtime/vm/debugger_api_impl.cc
===================================================================
--- runtime/vm/debugger_api_impl.cc	(revision 17321)
+++ runtime/vm/debugger_api_impl.cc	(working copy)
@@ -361,6 +361,42 @@
 }
 
 
+DART_EXPORT Dart_Handle Dart_OneTimeBreakAtEntry(
+                            Dart_Handle library_in,
+                            Dart_Handle class_name_in,
+                            Dart_Handle function_name_in) {
+  Isolate* isolate = Isolate::Current();
+  DARTSCOPE(isolate);
+  UNWRAP_AND_CHECK_PARAM(Library, library, library_in);
+  UNWRAP_AND_CHECK_PARAM(String, class_name, class_name_in);
+  UNWRAP_AND_CHECK_PARAM(String, function_name, function_name_in);
+
+  const char* msg = CheckIsolateState(isolate);
+  if (msg != NULL) {
+    return Api::NewError("%s", msg);
+  }
+
+  // Resolve the breakpoint target function.
+  Debugger* debugger = isolate->debugger();
+  const Function& bp_target = Function::Handle(
+      debugger->ResolveFunction(library, class_name, function_name));
+  if (bp_target.IsNull()) {
+    const bool toplevel = class_name.Length() == 0;
+    return Api::NewError("%s: could not find function '%s%s%s'",
+                         CURRENT_FUNC,
+                         toplevel ? "" : class_name.ToCString(),
+                         toplevel ? "" : ".",
+                         function_name.ToCString());
+  }
+
+  debugger->OneTimeBreakAtEntry(bp_target);
+  return Api::True(isolate);
+}
+
+
+
+
+
 DART_EXPORT Dart_Handle Dart_RemoveBreakpoint(intptr_t bp_id) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);