Implement growth policy for old space using time and space signals.

runtime/vm/scavenger.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_SCAVENGER_H_
 #define VM_SCAVENGER_H_
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
@@ skipping 55 matching lines @@
   uword* TopAddress() { return &top_; }
   uword* EndAddress() { return &end_; }
   static intptr_t top_offset() { return OFFSET_OF(Scavenger, top_); }
   static intptr_t end_offset() { return OFFSET_OF(Scavenger, end_); }
 
   intptr_t in_use() const { return (top_ - FirstObjectStart()); }
   intptr_t capacity() const { return space_->size(); }
 
   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
+  // Returns true if the last scavenge had a promotion failure.
+  bool HadPromotionFailure() {
+    return had_promotion_failure_;
+  }
+
  private:
   uword FirstObjectStart() const { return to_->start() | object_alignment_; }
   void Prologue(Isolate* isolate, bool invoke_api_callbacks);
   void IterateRoots(Isolate* isolate,
                     ObjectPointerVisitor* visitor,
                     bool visit_prologue_weak_persistent_handles);
   void IterateWeakReferences(Isolate* isolate, ObjectPointerVisitor* visitor);
   void IterateWeakRoots(Isolate* isolate,
                         HandleVisitor* visitor,
                         bool visit_prologue_weak_persistent_handles);
@@ skipping 51 matching lines @@
 
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // VM_SCAVENGER_H_