Add missing HeapCompact DCHECK().

third_party/WebKit/Source/platform/heap/HeapCompact.cpp

Index: third_party/WebKit/Source/platform/heap/HeapCompact.cpp
diff --git a/third_party/WebKit/Source/platform/heap/HeapCompact.cpp b/third_party/WebKit/Source/platform/heap/HeapCompact.cpp
index 24d47af4b5e89346a2f177e7861e04b407dcd734..4a0498193d22c150ed984022a16afd347a35f568 100644
--- a/third_party/WebKit/Source/platform/heap/HeapCompact.cpp
+++ b/third_party/WebKit/Source/platform/heap/HeapCompact.cpp
@@ -87,7 +87,7 @@ class HeapCompact::MovableObjectFixups final {
     if (LIKELY(!m_relocatablePages.contains(slotPage)))
       return;
 #if ENABLE(ASSERT)
-    slotPage->contains(slotAddress);
+    DCHECK(slotPage->contains(slotAddress));
 #endif
     // Unlikely case, the slot resides on a compacting arena's page.
     //  => It is an 'interior slot' (interior to a movable backing store.)