Remove prototype checks for leaf maps in optimized code.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 1f6e7cc0878c87a8630b77f4e05bd40f7d89cc18..130d3a54d9336e426edb36ca06001170b85ce341 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4706,7 +4706,10 @@ class DependentCodes: public FixedArray {
     // Group of codes that weakly embed this map and depend on being
     // deoptimized when the map is garbage collected.
     kWeaklyEmbeddedGroup,
-    kGroupCount = kWeaklyEmbeddedGroup + 1
+    // Group of codes that omitted prototype check for a prototype with this map
+    // and depend on being deoptimized when map layout changes.
+    kPrototypeCheckGroup,
+    kGroupCount = kPrototypeCheckGroup + 1
   };
   // Array for holding the index of the first code object of each group.
   // The last element stores the total number of code objects.
@@ -5182,6 +5185,8 @@ class Map: public HeapObject {
   inline void AddDependentCode(DependentCodes::DependencyGroup group,
                                Handle<Code> code);
 
+  void DeoptimizeDependentCodes(DependentCodes::DependencyGroup group);
+
   // Dispatched behavior.
   DECLARE_PRINTER(Map)
   DECLARE_VERIFIER(Map)