Move platform abstraction to base library

src/mark-compact.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_MARK_COMPACT_H_
 #define V8_MARK_COMPACT_H_
 
 #include "src/compiler-intrinsics.h"
 #include "src/spaces.h"
 
@@ skipping 717 matching lines @@
 
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;
 
   bool was_marked_incrementally_;
 
   // True if concurrent or parallel sweeping is currently in progress.
   bool sweeping_pending_;
 
-  Semaphore pending_sweeper_jobs_semaphore_;
+  base::Semaphore pending_sweeper_jobs_semaphore_;
 
   bool sequential_sweeping_;
 
   // A pointer to the current stack-allocated GC tracer object during a full
   // collection (NULL before and after).
   GCTracer* tracer_;
 
   SlotsBufferAllocator slots_buffer_allocator_;
 
   SlotsBuffer* migration_slots_buffer_;
@@ skipping 230 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_