[heap] Remove obsolete Heap::sweep_generation field.

src/heap/heap.cc

 // Copyright 2012 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.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 53 matching lines @@
                                    kInitalOldGenerationLimitFactor),
       old_generation_size_configured_(false),
       max_executable_size_(256ul * (kPointerSize / 4) * MB),
       // Variables set based on semispace_size_ and old_generation_size_ in
       // ConfigureHeap.
       // Will be 4 * reserved_semispace_size_ to ensure that young
       // generation can be aligned to its size.
       maximum_committed_(0),
       survived_since_last_expansion_(0),
       survived_last_scavenge_(0),
-      sweep_generation_(0),
       always_allocate_scope_depth_(0),
       contexts_disposed_(0),
       global_ic_age_(0),
       scan_on_scavenge_pages_(0),
       new_space_(this),
       old_space_(NULL),
       code_space_(NULL),
       map_space_(NULL),
       lo_space_(NULL),
       gc_state_(NOT_IN_GC),
@@ skipping 1116 matching lines @@
     // We speed up the incremental marker if it is running so that it
     // does not fall behind the rate of promotion, which would cause a
     // constantly growing old space.
     incremental_marking()->NotifyOfHighPromotionRate();
   }
 
   if (collector == MARK_COMPACTOR) {
     UpdateOldGenerationAllocationCounter();
     // Perform mark-sweep with optional compaction.
     MarkCompact();
-    sweep_generation_++;
     old_gen_exhausted_ = false;
     old_generation_size_configured_ = true;
     // This should be updated before PostGarbageCollectionProcessing, which can
     // cause another GC. Take into account the objects promoted during GC.
     old_generation_allocation_counter_ +=
         static_cast<size_t>(promoted_objects_size_);
     old_generation_size_at_last_gc_ = PromotedSpaceSizeOfObjects();
   } else {
     Scavenge();
   }
@@ skipping 5681 matching lines @@
     *object_type = "CODE_TYPE";                                                \
     *object_sub_type = "CODE_AGE/" #name;                                      \
     return true;
     CODE_AGE_LIST_COMPLETE(COMPARE_AND_RETURN_NAME)
 #undef COMPARE_AND_RETURN_NAME
   }
   return false;
 }
 }  // namespace internal
 }  // namespace v8