Change age-mark to not expect pages to be in increasing order.

src/spaces.cc

Index: src/spaces.cc
diff --git a/src/spaces.cc b/src/spaces.cc
index 2671ce9e6ed90f120554987840c613f4b2a37ba3..40a981d226f355c4d00dac772a53f4cc0f43d7b8 100644
--- a/src/spaces.cc
+++ b/src/spaces.cc
@@ -1279,6 +1279,7 @@ void SemiSpace::FlipPages(intptr_t flags, intptr_t mask) {
     if (becomes_to_space) {
       page->ClearFlag(MemoryChunk::IN_FROM_SPACE);
       page->SetFlag(MemoryChunk::IN_TO_SPACE);
+      page->ClearFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK);
     } else {
       page->SetFlag(MemoryChunk::IN_FROM_SPACE);
       page->ClearFlag(MemoryChunk::IN_TO_SPACE);
@@ -1590,6 +1591,16 @@ void NewSpace::RecordPromotion(HeapObject* obj) {
 #endif  // defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
 
 
+void SemiSpace::set_age_mark(Address mark) {
+  age_mark_ = mark;
+  ASSERT(to_space_.Contains(mark));
+  // Mark all pages up to the one containing mark.
+  NewSpacePageIterator it(space_low(), mark);
+  while (it.has_next()) {
+    it.next()->SetFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK);
+  }
+}
+
 // -----------------------------------------------------------------------------
 // Free lists for old object spaces implementation