Fix some missing includes and forward declarations.

src/circular-queue.h

 // Copyright 2010 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 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_CIRCULAR_QUEUE_H_
 #define V8_CIRCULAR_QUEUE_H_
 
+#include "atomicops.h"
 #include "v8globals.h"
 
 namespace v8 {
 namespace internal {
 
 
 // Lock-free cache-friendly sampling circular queue for large
 // records. Intended for fast transfer of large records between a
 // single producer and a single consumer. If the queue is full,
 // StartEnqueue will return NULL. The queue is designed with
@@ skipping 40 matching lines @@
   V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry* enqueue_pos_;
   V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry* dequeue_pos_;
 
   DISALLOW_COPY_AND_ASSIGN(SamplingCircularQueue);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_CIRCULAR_QUEUE_H_