Transmit breakpoint id on paused event

runtime/vm/debugger.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_DEBUGGER_H_
 #define VM_DEBUGGER_H_
 
 #include "include/dart_debugger_api.h"
 
 #include "vm/object.h"
@@ skipping 236 matching lines @@
  public:
   enum EventType {
     kBreakpointReached = 1,
     kBreakpointResolved = 2,
     kExceptionThrown = 3,
     kIsolateCreated = 4,
     kIsolateShutdown = 5,
     kIsolateInterrupted = 6,
   };
   struct DebuggerEvent {
+    explicit DebuggerEvent(EventType event_type)
+        : type(event_type) {
+      top_frame = NULL;
+      breakpoint = NULL;
+      exception = NULL;
+      isolate_id = 0;
+    }
     EventType type;
-    union {
-      ActivationFrame* top_frame;
-      SourceBreakpoint* breakpoint;
-      const Object* exception;
-      Dart_Port isolate_id;
-    };
+    // type == kBreakpointReached.
+    ActivationFrame* top_frame;
+    // type == kBreakpointResolved, kBreakpointReached.
+    SourceBreakpoint* breakpoint;
+    // type == kExceptionThrown.
+    const Object* exception;
+    // type == kIsolate(Created|Shutdown|Interrupted).
+    Dart_Port isolate_id;
   };
   typedef void EventHandler(DebuggerEvent *event);
 
   Debugger();
   ~Debugger();
 
   void Initialize(Isolate* isolate);
   void Shutdown();
 
   void NotifyCompilation(const Function& func);
@@ skipping 110 matching lines @@
                                            const Code& code,
                                            const Array& deopt_frame,
                                            intptr_t deopt_frame_offset,
                                            ActivationFrame* callee_activation,
                                            const Context& entry_ctx);
   static RawArray* DeoptimizeToArray(Isolate* isolate,
                                      StackFrame* frame,
                                      const Code& code);
   static DebuggerStackTrace* CollectStackTraceNew();
   void SignalBpResolved(SourceBreakpoint *bpt);
-  void SignalPausedEvent(ActivationFrame* top_frame);
+  void SignalPausedEvent(ActivationFrame* top_frame,
+                         SourceBreakpoint* bpt);
 
   intptr_t nextId() { return next_id_++; }
 
   bool ShouldPauseOnException(DebuggerStackTrace* stack_trace,
                               const Instance& exc);
 
   void CollectLibraryFields(const GrowableObjectArray& field_list,
                             const Library& lib,
                             const String& prefix,
                             bool include_private_fields);
@@ skipping 31 matching lines @@
 
   friend class Isolate;
   friend class SourceBreakpoint;
   DISALLOW_COPY_AND_ASSIGN(Debugger);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_DEBUGGER_H_