Web Inspector: Canvas tab: ensure that the Recording TreeOutline has a specified height for virtualization

• Component: Web Inspector
• Status: RESOLVED FIXED

[Devin Rousso]

The Recording TreeOutline was added to its own container, but that container's height was never constrained, meaning that it's height is the full height of all the TreeElement children.  Since TreeOutline uses `offsetHeight` to determine how many elements to show, the virtualization logic of TreeOutline then proceeds to add everything back to the DOM since it thinks it has room.

[Devin Rousso]

Created attachment 334409 [details]
Patch

[Radar WebKit Bug Importer]

<rdar://problem/37758441>

[Matt Baker]

Comment on attachment 334409 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=334409&action=review

r-, because it looks like this breaks the recording tree outline:

1. Goto https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API/Tutorial/Basic_animations
2. Record frames from "a looping panorama" demo
3. Open recording, expand first frame
  => No child elements

> Source/WebInspectorUI/UserInterface/Views/TreeOutline.js:716
> +        if (!isNaN(this._virtualizedPreviousFirstItem) && Math.abs(firstItem - this._virtualizedPreviousFirstItem) < numberVisible)

Why is this needed? The bug title/summary gives the impression that the problem is with how TreeOutline is used in the CanvasSidebarPanel, not with TreeOutline itself. Please add a clarifying comment to the change log.

[Devin Rousso]

Comment on attachment 334409 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=334409&action=review

>> Source/WebInspectorUI/UserInterface/Views/TreeOutline.js:716
>> +        if (!isNaN(this._virtualizedPreviousFirstItem) && Math.abs(firstItem - this._virtualizedPreviousFirstItem) < numberVisible)
> 
> Why is this needed? The bug title/summary gives the impression that the problem is with how TreeOutline is used in the CanvasSidebarPanel, not with TreeOutline itself. Please add a clarifying comment to the change log.

This is what caused the breakage.  I was trying to optimize the virtualization functionality, but I see that it needs some tweaking.  :P

[Devin Rousso]

Created attachment 335208 [details]
Patch

[Matt Baker]

Comment on attachment 335208 [details]
Patch

r=me

[WebKit Commit Bot]

Comment on attachment 335208 [details]
Patch

Clearing flags on attachment: 335208

Committed r229377: <https://trac.webkit.org/changeset/229377>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.