[heap] Add the free remainder of a black page to the free list.

src/heap/spaces.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include <list>
 
 #include "src/allocation.h"
@@ skipping 647 matching lines @@
 
   Address area_start() { return area_start_; }
   Address area_end() { return area_end_; }
   int area_size() { return static_cast<int>(area_end() - area_start()); }
 
   bool CommitArea(size_t requested);
 
   // Approximate amount of physical memory committed for this chunk.
   size_t CommittedPhysicalMemory() { return high_water_mark_.Value(); }
 
+  Address HighWaterMark() { return address() + high_water_mark_.Value(); }
+
   int progress_bar() {
     DCHECK(IsFlagSet(HAS_PROGRESS_BAR));
     return progress_bar_;
   }
 
   void set_progress_bar(int progress_bar) {
     DCHECK(IsFlagSet(HAS_PROGRESS_BAR));
     progress_bar_ = progress_bar;
   }
 
@@ skipping 2497 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_H_