The delete logic sees the caption inside the image as a valid place to
put a cursor and therefore a valid range to delete up to. This means
paragraphs can be merged into image captions by backspacing them in.
Add in a flag that keeps track of whether we are in a handlesOwnChildren
node so we can skip over them.
Bug: 57927
Change-Id: I19e91d2d3a871806d207cbd419f4a45e41d69dc0
Instead select the node and require the user to press delete
again if they really meant to delete the node.
Also test cases!
Bug: 55336
Change-Id: I66520e18740e78ce6313f9b31bb575d06b91bea8