Rework service extensions to be safe

runtime/vm/isolate.h

 // Copyright (c) 2013, 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_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 689 matching lines @@
     return deoptimized_code_array_;
   }
   void set_deoptimized_code_array(const GrowableObjectArray& value);
   void TrackDeoptimizedCode(const Code& code);
 
   bool compilation_allowed() const { return compilation_allowed_; }
   void set_compilation_allowed(bool allowed) {
     compilation_allowed_ = allowed;
   }
 
+  RawGrowableObjectArray* pending_extension_calls() const {
+    return pending_extension_calls_;
+  }
+  void set_pending_extension_calls(const GrowableObjectArray& value);

[turnidge, 2015/08/20 17:34:39]

Maybe make pending_extension_calls, set_pending_extension_calls, and
PrunePendingExtensionCalls private.

[Cutch, 2015/08/20 18:09:37]

Done.

+  RawObject* InvokePendingExtensionCalls();
+  RawGrowableObjectArray* PrunePendingExtensionCalls();
+  void AppendExtensionCall(const Instance& closure);
+
 #if defined(DEBUG)
 #define REUSABLE_HANDLE_SCOPE_ACCESSORS(object)                                \
   void set_reusable_##object##_handle_scope_active(bool value) {               \
     reusable_##object##_handle_scope_active_ = value;                          \
   }                                                                            \
   bool reusable_##object##_handle_scope_active() const {                       \
     return reusable_##object##_handle_scope_active_;                           \
   }
   REUSABLE_HANDLE_LIST(REUSABLE_HANDLE_SCOPE_ACCESSORS)
 #undef REUSABLE_HANDLE_SCOPE_ACCESSORS
@@ skipping 134 matching lines @@
 
   VMTagCounters vm_tag_counters_;
   uword user_tag_;
   RawGrowableObjectArray* tag_table_;
   RawUserTag* current_tag_;
   RawUserTag* default_tag_;
 
   RawGrowableObjectArray* collected_closures_;
   RawGrowableObjectArray* deoptimized_code_array_;
 
+  RawGrowableObjectArray* pending_extension_calls_;
+
   Metric* metrics_list_head_;
 
   Counters counters_;
 
   bool compilation_allowed_;
 
   // TODO(23153): Move this out of Isolate/Thread.
   CHA* cha_;
 
   // Isolate list next pointer.
@@ skipping 201 matching lines @@
   uint8_t* serialized_message_;
   intptr_t serialized_message_len_;
   Isolate::Flags isolate_flags_;
   bool paused_;
   bool errors_are_fatal_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_