Fix compilation on ARM and x64.

src/incremental-marking.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 142 matching lines @@
   inline void SetOldSpacePageFlags(MemoryChunk* chunk) {
     SetOldSpacePageFlags(chunk, IsMarking());
   }
 
   inline void SetNewSpacePageFlags(NewSpacePage* chunk) {
     SetNewSpacePageFlags(chunk, IsMarking());
   }
 
   MarkingDeque* marking_deque() { return &marking_deque_; }
 
+  bool IsCompacting() { return IsMarking() && is_compacting_; }
+
  private:
   void set_should_hurry(bool val) {
     should_hurry_ = val;
   }
 
   void ResetStepCounters() {
     steps_count_ = 0;
     steps_took_ = 0;
     steps_count_since_last_gc_ = 0;
     steps_took_since_last_gc_ = 0;
@@ skipping 34 matching lines @@
   int steps_count_since_last_gc_;
   double steps_took_since_last_gc_;
   bool should_hurry_;
   int allocation_marking_factor_;
   intptr_t allocated_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_INCREMENTAL_MARKING_H_