In Bug 178108, isolated heaps were introduced for all render tree objects. However, at least one class was missed (fixed by Bug 180010). It would be really useful to have a check-webkit-style checker that warns when WTF_MAKE_ISO_ALLOCATED or WTF_MAKE_ISO_ALLOCATED_IMPL are missing from a new or existing class.
One way to do this would be to match on class name (since we want all Render* classes to opt into ISO heaps), but that won't work if other classes start opting in as well. A better approach may be to figure out how to preprocess the header file (thus pulling in the base class declaration), and then check the base class declaration of the new/modified subclass to see if it's missing the WTF_MAKE_ISO_ALLOCATED macro. To check for the need for the WTF_MAKE_ISO_ALLOCATED_IMPL macro, we just need to check that the header file contains a WTF_MAKE_ISO_ALLOCATED macro within its class declaration. Obviously, the checker should check for both conditions: (a) using a macro when it shouldn't be used, and (b) omitting a macro when it should be used.