Creating a ChunkIterator allows you to iterate over the text in a
Layout::TextNode at your leisure by calling next() when you want
another chunk.
This is one of many steps towards improving inline layout.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
A label's format is: <label>Label text</label>
So, a TextNode is created as a child of the Label node, and EventHandler
will send events to the TextNode. This changes TextNode to accept mouse
events if its parent is a Label, and to forward those events upward.
The generic is<T>() uses dynamic_cast which is fine in the majority
of cases, but when one of them shows up in profiles, we can make it
faster by answering the is-a question manually.
