- Address review comments from https://codereview.chromium.org/474913004/

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 VM_HEAP_H_
 #define VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 44 matching lines @@
     kGCTestCase,
   };
 
   // Default allocation sizes in MB for the old gen and code heaps.
   static const intptr_t kHeapSizeInMWords = 128;
   static const intptr_t kHeapSizeInMB = kHeapSizeInMWords * kWordSize;
   static const intptr_t kCodeHeapSizeInMB = 18;
 
   ~Heap();
 
-  Scavenger* new_space() { return new_space_; }
-  PageSpace* old_space() { return old_space_; }
+  Scavenger* new_space() const { return new_space_; }
+  PageSpace* old_space() const { return old_space_; }
 
   uword Allocate(intptr_t size, Space space) {
     ASSERT(!read_only_);
     switch (space) {
       case kNew:
         // Do not attempt to allocate very large objects in new space.
         if (!IsAllocatableInNewSpace(size)) {
           return AllocateOld(size, HeapPage::kData);
         }
         return AllocateNew(size);
@@ skipping 267 matching lines @@
   NoHeapGrowthControlScope();
   ~NoHeapGrowthControlScope();
  private:
   bool current_growth_controller_state_;
   DISALLOW_COPY_AND_ASSIGN(NoHeapGrowthControlScope);
 };
 
 }  // namespace dart
 
 #endif  // VM_HEAP_H_