Issue 1983 - Dispatch onLoading event for prerendered pages

[Sebastian Noack, 2015-02-10 12:47:53]

It turned out that we can't deallocate the frame hierarchy on navigation, which
was causing the issue. However, dispatching ext.pages.onLoading before
navigation occurs, makes sense too. I realized that the tab doesn't change to
"loading" as reported by chrome.tabs.onUpdated, when the tab is prerendered. The
webNavigation API however, can be relied on.

[kzar, 2015-02-10 15:42:25]

LGTM

[Sebastian Noack, 2015-02-10 17:01:33]

Now it is getting complicated. I realized that Chrome is automatically resetting
the browser action on navigation. So we have to delay the "onLoading" event for
visible tabs until their status actually changes to "loading". However, the
"onUpdated" event isn't dispatched for prerendered tabs. So we have to keep
dispatching the "onLoading" immediately for prerendered tabs.

[Wladimir Palant, 2015-02-10 17:32:35]

LGTM

Quite a hack, but given
https://code.google.com/p/chromium/issues/detail?id=93646 this seems to be the
best we can do.

[kzar, 2015-02-10 17:37:20]

LGTM

(I found the last patchset much easier to understand, with the simplified
changes and the useful comment you added. Probably helped that I have been
reading through the related code this afternoon I guess too.)

[Sebastian Noack, 2015-02-10 17:37:25]

On 2015/02/10 17:32:35, Wladimir Palant wrote:
> LGTM
> 
> Quite a hack, but given
> https://code.google.com/p/chromium/issues/detail?id=93646 this seems to be the
> best we can do.

Yeah, I've reported a related issue quite some time ago:
https://code.google.com/p/chromium/issues/detail?id=418193

And finally found a way to workaround Chrome's silly pre-rendered tabs issue.
Also see: http://codereview.adblockplus.org/6089170179063808

[Sebastian Noack, 2015-02-10 17:37:25]

On 2015/02/10 17:32:35, Wladimir Palant wrote:
> LGTM
> 
> Quite a hack, but given
> https://code.google.com/p/chromium/issues/detail?id=93646 this seems to be the
> best we can do.

Yeah, I've reported a related issue quite some time ago:
https://code.google.com/p/chromium/issues/detail?id=418193

And finally found a way to workaround Chrome's silly pre-rendered tabs issue.
Also see: http://codereview.adblockplus.org/6089170179063808