On trunk, we currently have a release assert that asserts that scripts are allowed when calling FrameLoader::stopAllLoaders. This is correct since stopAllLoaders might dispatch events. We should continue to have the release assert in trunk, because we should catch when this happens. However, there still might be cases where the assert fails, but the backtrace will turn out to be one where scripting could be allowed. The release assert in trunk will help us catch these cases. On the branch, however, we should avoid crashing in these cases, and replace the release assert with a debug assert. If approved, this patch should only land on a branch, not on trunk.