Add a VM page to the observatory.

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index c4277282e6bb293e399d1c9334b4ea2d90c170db..39b4ce2bf74672d1651c8e2f2d53355f3400cc9c 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -143,7 +143,7 @@ class Isolate : public BaseIsolate {
 
   int64_t start_time() const { return start_time_; }
 
-  Dart_Port main_port() { return main_port_; }
+  Dart_Port main_port() const { return main_port_; }
   void set_main_port(Dart_Port port) {
     ASSERT(main_port_ == 0);  // Only set main port once.
     main_port_ = port;
@@ -433,7 +433,7 @@ class Isolate : public BaseIsolate {
     return profiler_data_;
   }
 
-  void PrintToJSONStream(JSONStream* stream);
+  void PrintToJSONStream(JSONStream* stream, bool ref = true);
 
   void set_thread_state(InterruptableThreadState* state) {
     ASSERT((thread_state_ == NULL) || (state == NULL));