1450189 - Don't invalidate display items when a frame gets a new style context

Status: RESOLVED FIXED

(Core :: Web Painting, enhancement, P2)

Description

[Matt Woodrow (:mattwoodrow)]

We currently invalidate all display items for a frame (and all descendants of that frame) whenever we get a new style context, even though the relevant rendering might not have changed (this happens frequently on gmail).

We invalidate display items, since the sometimes have raw pointers to style data, which will be dangling after we change style context.

Instead we can just hold a strong pointer to the style context, and if anything relevant changed then we'll get a call to InvalidateFrame() to trigger the display item invalidation.

Comment 1

[Matt Woodrow (:mattwoodrow)]

Attachment: Don't invalidate display items when we get a new style context

Comment 2

[Miko Mynttinen]

Comment on attachment 8963872 [details] [diff] [review]
Don't invalidate display items when we get a new style context

Review of attachment 8963872 [details] [diff] [review]:
-----------------------------------------------------------------

LGTM.

::: layout/painting/nsDisplayList.cpp
@@ +3678,5 @@
>    if ((drawBackgroundColor && color != NS_RGBA(0,0,0,0)) ||
>        aBuilder->IsForEventDelivery()) {
>      Maybe<DisplayListClipState::AutoSaveRestore> clipState;
>      nsRect bgColorRect = bgRect;
> +    if (bgSC && !aBuilder->IsForEventDelivery()) {

There is a call bg->BottomLayer() below (and other calls as well) that might now be nullptr, if the background is themed.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/79da39e0fd79
Don't invalidate display items when we get a new style context. r=miko

Comment 4

[Eliza Balazs [:ebalazs_]]

https://hg.mozilla.org/mozilla-central/rev/79da39e0fd79