Make objects embedded in optimized code weak.

src/mark-compact.h

Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index 4474864feb85808970fbed1979ec90be8d36e28a..b6ec8997de91932a8adbe8584ac5d96d6135eebf 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -637,7 +637,7 @@ class MarkCompactCollector {
   void VerifyMarkbitsAreClean();
   static void VerifyMarkbitsAreClean(PagedSpace* space);
   static void VerifyMarkbitsAreClean(NewSpace* space);
-  void VerifyWeakEmbeddedMapsInOptimizedCode();
+  void VerifyWeakEmbeddedMapsAndObjectsInOptimizedCode();
   void VerifyOmittedMapChecks();
 #endif
 
@@ -735,6 +735,10 @@ class MarkCompactCollector {
     return sequential_sweeping_;
   }
 
+  // Mark the global table which maps weak objects to dependent code without
+  // marking its contents.
+  void MarkWeakObjectToCodeTable();
+
  private:
   MarkCompactCollector();
   ~MarkCompactCollector();
@@ -884,7 +888,7 @@ class MarkCompactCollector {
   void ClearNonLivePrototypeTransitions(Map* map);
   void ClearNonLiveMapTransitions(Map* map, MarkBit map_mark);
 
-  void ClearAndDeoptimizeDependentCode(Map* map);
+  void ClearAndDeoptimizeDependentCode(DependentCode* dependent_code);
   void ClearNonLiveDependentCode(DependentCode* dependent_code);
 
   // Marking detaches initial maps from SharedFunctionInfo objects