[heap] pause/resume inline allocation observers around scavenge

test/cctest/test-spaces.cc

Index: test/cctest/test-spaces.cc
diff --git a/test/cctest/test-spaces.cc b/test/cctest/test-spaces.cc
index accf9334ede1279aa098e36c6807feabc353dabe..6c3591a855abe4cb3f50c7e550c7276e85ffab85 100644
--- a/test/cctest/test-spaces.cc
+++ b/test/cctest/test-spaces.cc
@@ -872,10 +872,24 @@ UNINITIALIZED_TEST(InlineAllocationObserver) {
     CHECK_EQ(observer1.count(), 20);  // no more notifications.
     CHECK_EQ(observer2.count(), 3);   // this one is still active.
 
+    // Ensure that Pause/ResumeInlineAllocationObservers work correctly.
+    AllocateUnaligned(new_space, 48);
+    CHECK_EQ(observer2.count(), 3);
+    new_space->PauseInlineAllocationObservers();
+    CHECK_EQ(observer2.count(), 3);
+    AllocateUnaligned(new_space, 384);
+    CHECK_EQ(observer2.count(), 3);
+    new_space->ResumeInlineAllocationObservers();
+    CHECK_EQ(observer2.count(), 3);
+    // Coupled with the 48 bytes allocated before the pause, another 48 bytes
+    // allocated here should trigger a notification.
+    AllocateUnaligned(new_space, 48);
+    CHECK_EQ(observer2.count(), 4);
+
     new_space->RemoveInlineAllocationObserver(&observer2);
     AllocateUnaligned(new_space, 384);
     CHECK_EQ(observer1.count(), 20);
-    CHECK_EQ(observer2.count(), 3);
+    CHECK_EQ(observer2.count(), 4);
   }
   isolate->Dispose();
 }