Merged r16150, r16174, r16175 into 3.19 branch.

src/assert-scope.h

Index: src/assert-scope.h
diff --git a/src/assert-scope.h b/src/assert-scope.h
index 13adbd0f9c5179a850194f9d86ac66cc2cf8fed8..269b280d027bd3ff42f3bfc84d255ae4653f3f0e 100644
--- a/src/assert-scope.h
+++ b/src/assert-scope.h
@@ -41,6 +41,7 @@ enum PerThreadAssertType {
   HANDLE_ALLOCATION_ASSERT,
   HANDLE_DEREFERENCE_ASSERT,
   DEFERRED_HANDLE_DEREFERENCE_ASSERT,
+  CODE_DEPENDENCY_CHANGE_ASSERT,
   LAST_PER_THREAD_ASSERT_TYPE
 };
 
@@ -170,6 +171,14 @@ typedef PerThreadAssertScope<DEFERRED_HANDLE_DEREFERENCE_ASSERT, false>
 typedef PerThreadAssertScope<DEFERRED_HANDLE_DEREFERENCE_ASSERT, true>
     AllowDeferredHandleDereference;
 
+// Scope to document where we do not expect deferred handles to be dereferenced.
+typedef PerThreadAssertScope<CODE_DEPENDENCY_CHANGE_ASSERT, false>
+    DisallowCodeDependencyChange;
+
+// Scope to introduce an exception to DisallowDeferredHandleDereference.
+typedef PerThreadAssertScope<CODE_DEPENDENCY_CHANGE_ASSERT, true>
+    AllowCodeDependencyChange;
+
 } }  // namespace v8::internal
 
 #endif  // V8_ASSERT_SCOPE_H_