Move atomic ops and related files to base library

src/objects-visiting.h

Index: src/objects-visiting.h
diff --git a/src/objects-visiting.h b/src/objects-visiting.h
index fb66387d323240b64ffe93416821e2edc8035576..f6fda9df0a2c9ee0deff359f4a57454d020e9b99 100644
--- a/src/objects-visiting.h
+++ b/src/objects-visiting.h
@@ -138,7 +138,7 @@ class VisitorDispatchTable {
     // every element of callbacks_ array will remain correct
     // pointer (memcpy might be implemented as a byte copying loop).
     for (int i = 0; i < StaticVisitorBase::kVisitorIdCount; i++) {
-      NoBarrier_Store(&callbacks_[i], other->callbacks_[i]);
+      base::NoBarrier_Store(&callbacks_[i], other->callbacks_[i]);
     }
   }
 
@@ -152,7 +152,7 @@ class VisitorDispatchTable {
 
   void Register(StaticVisitorBase::VisitorId id, Callback callback) {
     ASSERT(id < StaticVisitorBase::kVisitorIdCount);  // id is unsigned.
-    callbacks_[id] = reinterpret_cast<AtomicWord>(callback);
+    callbacks_[id] = reinterpret_cast<base::AtomicWord>(callback);
   }
 
   template<typename Visitor,
@@ -184,7 +184,7 @@ class VisitorDispatchTable {
   }
 
  private:
-  AtomicWord callbacks_[StaticVisitorBase::kVisitorIdCount];
+  base::AtomicWord callbacks_[StaticVisitorBase::kVisitorIdCount];
 };