Add support for a target new space size

src/heap/heap.h

 // 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.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 
 #include "src/allocation.h"
@@ skipping 548 matching lines @@
   // the young generation, we reserve 4 times the amount needed for a
   // semi space.  The young generation consists of two semi spaces and
   // we reserve twice the amount needed for those in order to ensure
   // that new space can be aligned to its size.
   intptr_t MaxReserved() {
     return 4 * reserved_semispace_size_ + max_old_generation_size_;
   }
   int MaxSemiSpaceSize() { return max_semi_space_size_; }
   int ReservedSemiSpaceSize() { return reserved_semispace_size_; }
   int InitialSemiSpaceSize() { return initial_semispace_size_; }
+  int TargetSemiSpaceSize() { return target_semispace_size_; }
   intptr_t MaxOldGenerationSize() { return max_old_generation_size_; }
   intptr_t MaxExecutableSize() { return max_executable_size_; }
 
   // Returns the capacity of the heap in bytes w/o growing. Heap grows when
   // more spaces are needed until it reaches the limit.
   intptr_t Capacity();
 
   // Returns the amount of memory currently committed for the heap.
   intptr_t CommittedMemory();
 
@@ skipping 882 matching lines @@
   // This can be calculated directly from a pointer to the heap; however, it is
   // more expedient to get at the isolate directly from within Heap methods.
   Isolate* isolate_;
 
   Object* roots_[kRootListLength];
 
   size_t code_range_size_;
   int reserved_semispace_size_;
   int max_semi_space_size_;
   int initial_semispace_size_;
+  int target_semispace_size_;
   intptr_t max_old_generation_size_;
   intptr_t max_executable_size_;
   intptr_t maximum_committed_;
 
   // For keeping track of how much data has survived
   // scavenge since last new space expansion.
   int survived_since_last_expansion_;
 
   // For keeping track on when to flush RegExp code.
   int sweep_generation_;
@@ skipping 1059 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_