Revert "Moves the top_ and end_ words of the Scavenger into mutator thread."

runtime/vm/heap.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 RUNTIME_VM_HEAP_H_
 #define RUNTIME_VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 117 matching lines @@
   void SetGrowthControlState(bool state);
   bool GrowthControlState();
 
   // Protect access to the heap. Note: Code pages are made
   // executable/non-executable when 'read_only' is true/false, respectively.
   void WriteProtect(bool read_only);
   void WriteProtectCode(bool read_only) {
     old_space_.WriteProtectCode(read_only);
   }
 
+  // Accessors for inlined allocation in generated code.
+  static intptr_t TopOffset(Space space);
+  static intptr_t EndOffset(Space space);
+
   // Initialize the heap and register it with the isolate.
   static void Init(Isolate* isolate,
                    intptr_t max_new_gen_words,
                    intptr_t max_old_gen_words,
                    intptr_t max_external_words);
 
   // Writes a suitable name for a VM region in the heap into the buffer `name`.
   static void RegionName(Heap* heap,
                          Space space,
                          char* name,
@@ skipping 184 matching lines @@
   bool BeginNewSpaceGC(Thread* thread);
   void EndNewSpaceGC();
   bool BeginOldSpaceGC(Thread* thread);
   void EndOldSpaceGC();
 
   void AddRegionsToObjectSet(ObjectSet* set) const;
 
   Isolate* isolate_;
 
   // The different spaces used for allocation.
-  Scavenger new_space_;
+  ALIGN8 Scavenger new_space_;
   PageSpace old_space_;
 
   WeakTable* new_weak_tables_[kNumWeakSelectors];
   WeakTable* old_weak_tables_[kNumWeakSelectors];
 
   Monitor* barrier_;
   Monitor* barrier_done_;
 
   // GC stats collection.
   GCStats stats_;
@@ skipping 47 matching lines @@
 // Note: During this scope, the code pages are non-executable.
 class WritableVMIsolateScope : StackResource {
  public:
   explicit WritableVMIsolateScope(Thread* thread);
   ~WritableVMIsolateScope();
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_HEAP_H_