Merge 10601,10602,10616,10625,10647 from the bleeding edge to the 3.8 branch.

src/mark-compact.h

Index: src/mark-compact.h
===================================================================
--- src/mark-compact.h	(revision 10927)
+++ src/mark-compact.h	(working copy)
@@ -374,7 +374,7 @@
   static const int kNumberOfElements = 1021;
 
  private:
-  static const int kChainLengthThreshold = 6;
+  static const int kChainLengthThreshold = 15;
 
   intptr_t idx_;
   intptr_t chain_length_;
@@ -441,8 +441,13 @@
   // Performs a global garbage collection.
   void CollectGarbage();
 
-  bool StartCompaction();
+  enum CompactionMode {
+    INCREMENTAL_COMPACTION,
+    NON_INCREMENTAL_COMPACTION
+  };
 
+  bool StartCompaction(CompactionMode mode);
+
   void AbortCompaction();
 
   // During a full GC, there is a stack-allocated GCTracer that is used for
@@ -572,6 +577,8 @@
   // heap.
   bool sweep_precisely_;
 
+  bool reduce_memory_footprint_;
+
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;