Reland r24563 and r24564 with fixes cumbersome API leading to leaks.

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 <map>
-
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
 #include "vm/globals.h"
 #include "vm/raw_object.h"
 #include "vm/virtual_memory.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
@@ skipping 62 matching lines @@
     *end = to_->end();
   }
 
   // Returns true if the last scavenge had a promotion failure.
   bool HadPromotionFailure() {
     return had_promotion_failure_;
   }
 
   void WriteProtect(bool read_only);
 
-  void SetPeer(RawObject* raw_obj, void* peer);
-
-  void* GetPeer(RawObject* raw_obj);
-
-  int64_t PeerCount() const;
-
  private:
   // Ids for time and data records in Heap::GCStats.
   enum {
     // Time
     kVisitIsolateRoots = 0,
     kIterateStoreBuffers = 1,
     kProcessToSpace = 2,
     kIterateWeaks = 3,
     // Data
     kStoreBufferEntries = 0,
@@ skipping 30 matching lines @@
   uword PopFromPromotedStack() {
     uword result = *reinterpret_cast<uword*>(end_);
     end_ += sizeof(result);
     ASSERT(end_ <= to_->end());
     return result;
   }
   bool PromotedStackHasMore() const {
     return end_ < to_->end();
   }
 
-  void ProcessPeerReferents();
+  void ProcessWeakTables();
 
   VirtualMemory* space_;
   MemoryRegion* to_;
   MemoryRegion* from_;
 
   Heap* heap_;
 
-  typedef std::map<RawObject*, void*> PeerTable;
-  PeerTable peer_table_;
-
   // Current allocation top and end. These values are being accessed directly
   // from generated code.
   uword top_;
   uword end_;
 
   // A pointer to the first unscanned object.  Scanning completes when
   // this value meets the allocation top.
   uword resolved_top_;
 
   // Objects below this address have survived a scavenge.
   uword survivor_end_;
 
   // All object are aligned to this value.
   uword object_alignment_;
 
   // Keep track whether a scavenge is currently running.
   bool scavenging_;
   // Keep track whether the scavenge had a promotion failure.
   bool had_promotion_failure_;
 
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // VM_SCAVENGER_H_