Prerendered tabs aren't handled on Chrome

[sebastian]

How to reproduce

1. Visit any website, to make sure that it gets into the history, and will be suggested by the omnibox during auto-completion, in the future.
2. Open a new tab.
3. Begin to type the URL of the previously visited website.
4. Wait for the URL to be auto-completed.
5. Wait a few more seconds to make sure the page gets prerendered.
6. Press enter.

Observed behaviour

If the page is whitelisted, the active ABP toolbar icon keeps showing, instead switching to the grayed-out icon. And if requests were blocked, no icon badge shows up. However, following error message shows up in the log of the background page:

Unchecked runtime.lastError while running browserAction.setBadgeText: No tab with id: 113.

That is because pre-rendered tabs, even though reported through the webRequest and webNavigation API, are considered invalid when specified in API calls like chrome.browserAction.setBadgeText().

Moreover, when a tab is replaced with a prerendered tab, the ​chrome.tabs.onReplaced event is triggered instead ​chrome.tabs.onRemoved, and Adblock Plus leaks memory.

Expected behaviour

The icon and badge should correctly indicate whether the page is whitelisted or how many requests were blocked. No error message should show up in the background page. And no memory should be leaked for replaced tabs. Therfore pre-rendered tabs must be handled explicitly, modifying the browser action icon and badge, and deallocating data, once the tab got replaced.

[sebastian]

​https://hg.adblockplus.org/adblockpluschrome/rev/9130cbf9434e