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 111 matching lines @@
   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);

[rmacnak, 2017/06/22 22:31:50]

Both should be unused, no?

[danunez, 2017/06/30 20:35:57]

Yes, but I left this in for testing. Incoming set will remove them.

-  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);
 
   // Verify that all pointers in the heap point to the heap.
   bool Verify(MarkExpectation mark_expectation = kForbidMarked) const;
 
@@ skipping 243 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_