The crash test crashtests/407079-1.html cause the following assert in TouchCaret.cpp when native selection handles are enabled in Fennec: MOZ_Assert( 721): Assertion failure: mVisible
Created attachment 8685721 [details] [diff] [review] 0001-Bug-1223614-Enabling-native-selection-handles-in-Fennec-triggers-assert-when-non-visible-handles-are-moved-15111016-06a829e.patch
This will not be an issue. TouchCaret.h/.cpp is no longer used after bug 1215959.
I don't think this is an issue any more, as native selection handles *are* enabled in Fennec with APZ on nightly now.