Reapply r1900, r1897, r1895 with a fix....

src/spaces-inl.h

Index: src/spaces-inl.h
===================================================================
--- src/spaces-inl.h	(revision 1915)
+++ src/spaces-inl.h	(working copy)
@@ -64,15 +64,16 @@
 // PageIterator
 
 bool PageIterator::has_next() {
-  return cur_page_ != stop_page_;
+  return prev_page_ != stop_page_;
 }
 
 
 Page* PageIterator::next() {
   ASSERT(has_next());
-  Page* result = cur_page_;
-  cur_page_ = cur_page_->next_page();
-  return result;
+  prev_page_ = (prev_page_ == NULL)
+               ? space_->first_page_
+               : prev_page_->next_page();
+  return prev_page_;
 }