Sometimes, the root pipeline title is sent before the compositor has created the root pipeline, so also request the main page title once the initial frame tree has been sent.
When an iframe is created with display:none it sets the root layer to be
zero width and height. When updating the rect of the iframe from layout
send the entire rect rather than just the new origin, which handles the case
where the iframe has been made visible and now has a non-zero rect.
Sometimes, the root pipeline title is sent before the compositor
has created the root pipeline, so also request the main page
title once the initial frame tree has been sent.
This used to conflict with the util crate from the standard library, which
has long since been removed.
The import in layout has not been changed because of a conflict with the
util mod there.
The set_ids name is a holdover from a previous design and no longer
reflects what this method does. Instead move the content into
grant_paint_permission and rename it to
send_frame_tree_and_grant_paint_permission. Also move out the handling of
evicted iframes into its own method.
When the constellation change a FrameTree pipeline, it should send a
notification to the compositor, so that it can negotiate buffers from
the correct render task. This commit also migrates away from the
generalized FrameTreeUpdateMsg to ones specific to the situation at
hand. That turned out to be an unnecessary abstraction.
Instead of simply creating a new FrameTree when an iframe starts a
load, update the existing FrameTree's pipeline. This prevents the
FrameTree from accumulating many extra children.
Instead of cloning pipelines and storing them once per layer, store
them globally in the compositor and access them via id. This trades
lots of unnecessary duplication for a HashMap lookup.
It is possible for messages for defunct pipelines to arrive in the
compositor. If the compositor believes that the pipelines are in the
process of shutting down, simply ignore the messages. We still panic in
the case that the pipeline is totally unknown.
Fixes#3733.
Notes:
* This adds `#![allow(missing_copy_implementations)]` to components/*/lib.rs. I'm not sure how to approach the missing Copy warnings (are there things for which Copy should NOT be implemented, and how can I tell?) so I stuck this in to make life easier when looking through the warnings. I can easily remove this if necessary.
* This leaves the following type of warnings, which I couldn't figure out how to approach (I'll investigate it later if no one else wants to).
```
css/matching.rs:72:23: 72:35 warning: use of deprecated item: Use overloaded core::cmp::PartialEq, #[warn(deprecated)] on by default
css/matching.rs:72 this_as_query.equiv(other)
^~~~~~~~~~~~
css/matching.rs:95:10: 95:49 warning: use of deprecated item: Use overloaded core::cmp::PartialEq, #[warn(deprecated)] on by default
css/matching.rs:95 impl<'a> Equiv<ApplicableDeclarationsCacheEntry> for ApplicableDeclarationsCacheQuery<'a> {
```
The term "root layer" is used in the compositor to refer to both the
pipeline root layer and the page background layer. This can be quite
confusing. Instead, call the page background layer the "base layer,"
which is always the first child of the pipeline root layer.
