Trigger old-space GC when scavange made the external heap of old-space larger than max old-space si…

runtime/vm/pages.h

 // Copyright (c) 2011, 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_PAGES_H_
 #define VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/virtual_memory.h"
@@ skipping 203 matching lines @@
   void StartEndAddress(uword* start, uword* end) const;
 
   void SetGrowthControlState(bool state) {
     page_space_controller_.set_is_enabled(state);
   }
 
   bool GrowthControlState() {
     return page_space_controller_.is_enabled();
   }
 
+  bool NeedExternalGC() {
+    return used_in_words_ + ExternalInWords() > max_capacity_in_words_;
+  }
+
   void WriteProtect(bool read_only);
 
   void AddGCTime(int64_t micros) {
     gc_time_micros_ += micros;
   }
 
   int64_t gc_time_micros() const {
     return gc_time_micros_;
   }
 
@@ skipping 64 matching lines @@
   intptr_t collections_;
 
   friend class PageSpaceController;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // VM_PAGES_H_