Reland "[heap] Start sweeper tasks after evacuation" (second try).

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 8b26ae01386c43aead807365918fd7f7a6803eae..7d379490d9323f61f0d607453d5e8d11d76fab81 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -411,6 +411,10 @@ class MemoryChunk {
     return concurrent_sweeping_;
   }
 
+  bool SweepingDone() {
+    return concurrent_sweeping_state().Value() == kSweepingDone;
+  }
+
   // Manage live byte count, i.e., count of bytes in black objects.
   inline void ResetLiveBytes();
   inline void IncrementLiveBytes(int by);
@@ -735,10 +739,6 @@ class Page : public MemoryChunk {
     DCHECK(SweepingDone());
   }
 
-  bool SweepingDone() {
-    return concurrent_sweeping_state().Value() == kSweepingDone;
-  }
-
   void ResetFreeListStatistics();
 
   size_t AvailableInFreeList();