Fix clearing of dead dependent codes and verify weak embedded maps on full GC.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 5db1c954c3ea098fa66a716a0218e35fec270fc3..3cb14fc0ea6ceb8344387821e939c9e35bb16cf7 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1322,6 +1322,11 @@ class Heap {
 #ifdef VERIFY_HEAP
   // Verify the heap is in its normal state before or after a GC.
   void Verify();
+
+
+  bool weak_embedded_maps_verification_enabled() {
+    return no_weak_embedded_maps_verification_scope_depth_ == 0;
+  }
 #endif
 
 #ifdef DEBUG
@@ -2190,6 +2195,10 @@ class Heap {
   unsigned int gc_count_at_last_idle_gc_;
   int scavenges_since_last_idle_round_;
 
+#ifdef VERIFY_HEAP
+  int no_weak_embedded_maps_verification_scope_depth_;
+#endif
+
   static const int kMaxMarkSweepsInIdleRound = 7;
   static const int kIdleScavengeThreshold = 5;
 
@@ -2219,6 +2228,9 @@ class Heap {
   friend class MarkCompactCollector;
   friend class MarkCompactMarkingVisitor;
   friend class MapCompact;
+#ifdef VERIFY_HEAP
+  friend class NoWeakEmbeddedMapsVerificationScope;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(Heap);
 };
@@ -2279,6 +2291,14 @@ class AlwaysAllocateScope {
   DisallowAllocationFailure disallow_allocation_failure_;
 };
 
+#ifdef VERIFY_HEAP
+class NoWeakEmbeddedMapsVerificationScope {
+ public:
+  inline NoWeakEmbeddedMapsVerificationScope();
+  inline ~NoWeakEmbeddedMapsVerificationScope();
+};
+#endif
+
 
 // Visitor class to verify interior pointers in spaces that do not contain
 // or care about intergenerational references. All heap object pointers have to