[webkit-reviews] review granted: [Bug 64412] didFirstVisuallyNonEmptyLayout dispatched too early : [Attachment 100595] patch

[bugzilla-daemon at webkit.org]

Darin Adler <darin at apple.com> has granted Antti Koivisto <koivisto at iki.fi>'s
request for review:
Bug 64412: didFirstVisuallyNonEmptyLayout dispatched too early
https://bugs.webkit.org/show_bug.cgi?id=64412

Attachment 100595: patch
https://bugs.webkit.org/attachment.cgi?id=100595&action=review

------- Additional Comments from Darin Adler <darin at apple.com>
View in context: https://bugs.webkit.org/attachment.cgi?id=100595&action=review


> Source/WebCore/page/FrameView.cpp:2059
> -	   if (m_isVisuallyNonEmpty &&
m_firstVisuallyNonEmptyLayoutCallbackPending) {
> +
> +	   // Ensure that we always send this eventually.
> +	   if (!m_frame->document()->parsing())
> +	       m_isVisuallyNonEmpty = true;
> +
> +	   if (m_isVisuallyNonEmpty &&
!m_frame->document()->didLayoutWithPendingStylesheets() &&
m_firstVisuallyNonEmptyLayoutCallbackPending) {

There is nothing in the change log or code that explains why you added a new
check of didLayoutWithPendingStylesheets here.

> Source/WebCore/page/FrameView.h:231
> +    void incrementVisuallyNonEmptyPixelCount(const IntSize& size);

The name “size” here doesn’t add anything, so you should omit it.

> Source/WebCore/page/FrameView.h:461
> +    static const unsigned visualCharacterThreshold = 200;

Would like a why comment explaining where this threshold came from. There isn’t
even a comment explaining why we made visually non-empty a heuristic rather
than a more brittle but well defined mechanism. There should be.

> Source/WebCore/page/FrameView.h:470
> +    m_visuallyNonEmptyPixelCount += size.width() * size.height();

Any risk of overflow here?

> Source/WebCore/page/FrameView.h:471
> +    static const unsigned visualPixelThreshold = 256 * 256;

Same kind of comment about threshold needed as above.

> Source/WebCore/rendering/RenderImage.cpp:146
> +    if (!m_didIncrementVisuallyNonEmptyPixelCount) {
> +	  
view()->frameView()->incrementVisuallyNonEmptyPixelCount(m_imageResource->image
Size(1.0f));
> +	   m_didIncrementVisuallyNonEmptyPixelCount = true;
> +    }

Does this do the right thing for incrementally loading images? Seems like it
will only do the pixel count thing once, perhaps with a smaller size than the
actual final size?

> Source/WebCore/rendering/RenderText.cpp:114
> -    // FIXME: It would be better to call this only if
!m_text->containsOnlyWhitespace().
> -    // But that might slow things down, and maybe should only be done if
visuallyNonEmpty
> -    // is still false. Not making any change for now, but should consider in
the future.
> -    view()->frameView()->setIsVisuallyNonEmpty();
> +   
view()->frameView()->incrementVisuallyNonEmptyCharacterCount(m_text.length());

Not worried about cases where there is nothing but a lot of whitespace?