See example here:

    class GlDisplayHander::Core {
      ...
      runtime_->ui_task_runner()->PostTask(FROM_HERE, base::BindBlockArc(^() {
                                             [handler_delegate_ rendererTicked];
                                           }));
    };

https://cs.chromium.org/chromium/src/remoting/ios/display/gl_display_handler.mm?l=174&rcl=b8a6fd5abbbdb8471f49672b7ea71caa378328aa

It is thread unsafe to capture (or implicitly) C++ objects in an Objective-C block because the C++ object doesn't do ARC. In this case the app may occasionally (<10%) crash when disconnecting from the host because the block attempts to dereference |this| to get back |handler_delegate_| while |this| is being destroyed.
 

See example here:

    class GlDisplayHander::Core {
      ...
      runtime_->ui_task_runner()->PostTask(FROM_HERE, base::BindBlockArc(^() {
                                             [handler_delegate_ rendererTicked];
                                           }));
    };

https://cs.chromium.org/chromium/src/remoting/ios/display/gl_display_handler.mm?l=174&rcl=b8a6fd5abbbdb8471f49672b7ea71caa378328aa

It is thread unsafe to capture (or implicitly capture) C++ objects in an Objective-C block because the C++ object doesn't do ARC. In this case the app may occasionally (<10%) crash when disconnecting from the host because the block attempts to dereference |this| to get back |handler_delegate_| while |this| is being destroyed.