Removed dated Persistent<>::checkPointer() assert.

third_party/WebKit/Source/platform/heap/Persistent.h

Index: third_party/WebKit/Source/platform/heap/Persistent.h
diff --git a/third_party/WebKit/Source/platform/heap/Persistent.h b/third_party/WebKit/Source/platform/heap/Persistent.h
index 2527ce0ec1d0edd925bc877c4268a825c342496b..0f9e0a59bf7e6ec7a7b1fe85ab7ff1675aa3bc90 100644
--- a/third_party/WebKit/Source/platform/heap/Persistent.h
+++ b/third_party/WebKit/Source/platform/heap/Persistent.h
@@ -262,18 +262,6 @@ class PersistentBase {
         DCHECK_EQ(&current->heap(), &m_creationThreadState->heap());
       }
     }
-
-#if defined(ADDRESS_SANITIZER)
-    // ThreadHeap::isHeapObjectAlive(m_raw) checks that m_raw is a traceable
-    // object. In other words, it checks that the pointer is either of:
-    //
-    //   (a) a pointer to the head of an on-heap object.
-    //   (b) a pointer to the head of an on-heap mixin object.
-    //
-    // Otherwise, ThreadHeap::isHeapObjectAlive will crash when it calls
-    // header->checkHeader().
-    ThreadHeap::isHeapObjectAlive(m_raw);
-#endif
 #endif
   }