Replace SmartPointer<T> with unique_ptr<T>

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 326a59916b4c1fb6a26bd7085e78f17ccb11afa7..c035342bfa85058dd9be34024e17cbc6d5722be3 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -6,6 +6,7 @@
 #define V8_HEAP_SPACES_H_
 
 #include <list>
+#include <memory>
 
 #include "src/allocation.h"
 #include "src/base/atomic-utils.h"
@@ -928,7 +929,7 @@ class Space : public Malloced {
 #endif
 
  protected:
-  v8::base::SmartPointer<List<AllocationObserver*>> allocation_observers_;
+  std::unique_ptr<List<AllocationObserver*>> allocation_observers_;
   bool allocation_observers_paused_;
 
  private:
@@ -939,6 +940,8 @@ class Space : public Malloced {
   // Keeps track of committed memory in a space.
   intptr_t committed_;
   intptr_t max_committed_;
+
+  DISALLOW_COPY_AND_ASSIGN(Space);
 };