Oilpan: isHeapObjectAlive should not return true for cross thread objects

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

Index: third_party/WebKit/Source/platform/heap/Heap.h
diff --git a/third_party/WebKit/Source/platform/heap/Heap.h b/third_party/WebKit/Source/platform/heap/Heap.h
index 7246971d1fcbf46688f05ac4bf97834ca98033ab..4a15e29ad28cce179e48d3b1e241d440b4fe7677 100644
--- a/third_party/WebKit/Source/platform/heap/Heap.h
+++ b/third_party/WebKit/Source/platform/heap/Heap.h
@@ -248,9 +248,8 @@ class PLATFORM_EXPORT ThreadHeap {
     // threads.
     if (!ThreadState::current())
       return true;
-    if (&ThreadState::current()->heap() !=
-        &pageFromObject(object)->arena()->getThreadState()->heap())
-      return true;
+    DCHECK(&ThreadState::current()->heap() ==

[sof, 2017/03/28 19:50:09]

How does this work for CrossThreadWeakPersistent<> and handleWeakPersistent()'s
use of isHeapObjectAlive() ?

[sof, 2017/03/28 20:02:07]

The shouldTracePersistentNode() same-heap check should prevent cross-thread uses
of such persistents, so there can't be any confusion about where that weak
callback is used.

+           &pageFromObject(object)->arena()->getThreadState()->heap());
     return ObjectAliveTrait<T>::isHeapObjectAlive(object);
   }
   template <typename T>