1701567 - about:support was not re-rendered correctly with on Android

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Sotaro Ikeda [:sotaro]]

When Tabs were switched with about:support, sometimes about:support was not re-rendered correctly. It seems to related to content size change with/without IME.

Comment 1

[Sotaro Ikeda [:sotaro]]

The problem also happened with RenderCompositorSWGL and RenderCompositorEGL. The problem happened even when WebRrender always did full render.

I did not saw the problem when compositor was CompositorOGL.

Comment 2

[Sotaro Ikeda [:sotaro]]

When the problem happened, "GeckoView:SetActive" message handling took long time and no rendering after the message handling.

• https://searchfox.org/mozilla-central/rev/54f37fc1ac0f98b590af51e01ce82bb74179bf63/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java#2018
• https://searchfox.org/mozilla-central/rev/54f37fc1ac0f98b590af51e01ce82bb74179bf63/mobile/android/modules/geckoview/GeckoViewContent.jsm#151

nsWindow::Resize() and SyncResumeResizeCompositor() were handled before "GeckoView:SetActive" message handling. Though they triggers rendering.

Comment 3

[Sotaro Ikeda [:sotaro]]

With pref gfx.webrender.dl.dump-parent = true, display list seemed not updated to a new widget size.
nsWindow::OnSizeChanged() is expected to trigger reflow. But related nsViewManager::SetWindowDimensions() did not call DoSetWindowDimensions(), since related PresShell was not active. In this case, resize is delayed.

• https://searchfox.org/mozilla-central/rev/54f37fc1ac0f98b590af51e01ce82bb74179bf63/view/nsViewManager.cpp#222

PresShell became active by PresShell::SetIsActive() call. It was called like the following. When the problem happened, PresShell::SetIsActive() was delayed a lot.

GeckoSession.setActive(true) // GeckoSession.java
->mEventDispatcher.dispatch("GeckoView:SetActive", msg); // GeckoSession.java
->GeckoViewContent.onEvent() // GeckoViewContent.jsm
->case "GeckoView:SetActive": // GeckoViewContent.jsm
->BrowsingContext::DidSet()
->nsDocShell::ActivenessMaybeChanged()
->PresShell::SetIsActive(/* aIsActive */ true)

Comment 4

[Sotaro Ikeda [:sotaro]]

When the problem happened, WebRenderLayerManager::EndTransactionWithoutLayer() was not called since PresShell::SetIsActive(/* aIsActive */ true).

From it, the problem seems to be addressed, when GeckoView:SetActive message handling could trigger EndTransactionWithoutLayer().

Comment 5

[Sotaro Ikeda [:sotaro]]

Attachment: Bug 1701567 - Schedule paint when PresShell becomes active

Comment 6

[Sotaro Ikeda [:sotaro]]

We want to trigger rendering with "GeckoView:SetActive" message handling. Trigger rendering with "PresShell::SetIsActive(/* aIsActive */ true)" is simple implementation. Though I am not sure it is OK.

Comment 7

[Sotaro Ikeda [:sotaro]]

:mstange, do you have any ideas to trigger rendering with "GeckoView:SetActive" message handling?

Comment 8

[Markus Stange [:mstange]]

I don't know much about how tab switching interacts with presshell activeness on Android, or what the right place to trigger rendering is, or when and how GeckoView sends "GeckoView:SetActive" during tab switching.

Does your WIP patch work? It sounds reasonable enough.

Is about:support behaving differently from content tabs because it's rendered in the parent process? Do you know what the path from "GeckoView:SetActive" to rendering is for content processes?

Comment 9

[Sotaro Ikeda [:sotaro]]

(In reply to Markus Stange [:mstange] from comment #8)

Does your WIP patch work? It sounds reasonable enough.

Yes, it addressed the problem.

Is about:support behaving differently from content tabs because it's rendered in the parent process? Do you know what the path from "GeckoView:SetActive" to rendering is for content processes?

MozBrowser.docShellIsActive(val) seems to have a code to trigger rendering in content process.

• https://searchfox.org/mozilla-central/rev/e9fb777466c3af99998d8d8cabf7e9defbeef292/mobile/android/modules/geckoview/GeckoViewContent.jsm#152
• https://searchfox.org/mozilla-central/rev/e9fb777466c3af99998d8d8cabf7e9defbeef292/toolkit/content/widgets/browser-custom-element.js#416
• https://searchfox.org/mozilla-central/rev/e9fb777466c3af99998d8d8cabf7e9defbeef292/dom/ipc/BrowserHost.cpp#115
• https://searchfox.org/mozilla-central/rev/e9fb777466c3af99998d8d8cabf7e9defbeef292/dom/ipc/BrowserParent.cpp#3345
• https://searchfox.org/mozilla-central/rev/e9fb777466c3af99998d8d8cabf7e9defbeef292/dom/ipc/BrowserParent.cpp#3382

Comment 10

[Sotaro Ikeda [:sotaro]]

https://treeherder.mozilla.org/jobs?repo=try&revision=ccf7b00a3f3893e51c216788ff7292668ede06a7

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e261df7eded5
Schedule paint when PresShell becomes active r=mstange

Comment 12

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/e261df7eded5