Bug 146439 – Web page doesn't update its loading state when web process becomes suspended if there are pending network requests (XHR).

• Component: WebKit2
• Status: RESOLVED FIXED

[Yongjun Zhang]

When a web page starts a XHR request after the page is finished loading, we should take a background activity token and hold it until the request is cancelled or finished. Otherwise the WebContent process could be suspended since its activity token could drop to 0 after this point.

[Yongjun Zhang]

<rdar://problem/18846532>

[Yongjun Zhang]

Created attachment 255795 [details]
Patch.

[Yongjun Zhang]

Hmm, this fix could have the side effect of holding the web process too long if there is a long lasting XHR request. I need to work on a better fix.

[Yongjun Zhang]

Update the title to reflect the real problem.

[Yongjun Zhang]

Created attachment 255810 [details]
Patch v2.

[Simon Fraser (smfr)]

Comment on attachment 255810 [details]
Patch v2.

View in context: https://bugs.webkit.org/attachment.cgi?id=255810&action=review

> Source/WebKit2/UIProcess/WebPageProxy.h:821
> +    void processWillBecomeForground();

"processWillBecomeForground" -> processWillBecomeForeground

Comment on attachment 255810 [details]
Patch v2.

I don’t know which state transitions are possible. Is it a concern that the outcomes of the following transitions are different?
Foreground -> Suspended -> Background
Foreground -> Background

Is it a concern that this transition will fail to restore the state?
Foreground -> Suspended -> Background -> Suspended -> Foreground
(because on the second entry into Suspended, m_hasNetworkRequestsOnSuspended will change to false)

[Yongjun Zhang]

(In reply to comment #7)
> Comment on attachment 255810 [details]
> Patch v2.
> 
> I don’t know which state transitions are possible. Is it a concern that the
> outcomes of the following transitions are different?
> Foreground -> Suspended -> Background
> Foreground -> Background

I could be wrong, but based on code inspection and my own test, I didn't find a scenario where the web process could go from Suspended to Background.

> 
> Is it a concern that this transition will fail to restore the state?
> Foreground -> Suspended -> Background -> Suspended -> Foreground
> (because on the second entry into Suspended, m_hasNetworkRequestsOnSuspended
> will change to false)

Again, this ties to whether Suspended -> Background transition is possible.

Thanks for the review! I will fix the typo on commit.

[Yongjun Zhang]

Created attachment 255956 [details]
Patch for landing.

[WebKit Commit Bot]

Comment on attachment 255956 [details]
Patch for landing.

Clearing flags on attachment: 255956

Committed r186200: <http://trac.webkit.org/changeset/186200>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.