Bug 145948 – [WK2] API::Navigation objects are leaked on history navigation to HistoryItems in PageCache

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit2

[Chris Dumez]

API::Navigation objects are leaked on history navigation to HistoryItems in PageCache.

When WebPageProxy::goBack() is called:
1. We create a back/forward navigation item by calling m_navigationState->createBackForwardNavigation()
2. We send WebPage::GoBack IPC to the WebContent process with the navigationID that was just created
3. WebPage::goBack() does NOT update m_pendingNavigationID because item->isInPageCache() return true. As a result, the navigationID is ignored.
4. In FrameLoader::loadDifferentDocumentItem(), we get a CachedPage from the PageCache and we reuse the cached DocumentLoader (instead of creating a new one)
5. WebFrameLoaderClient::dispatchDecidePolicyForNavigationAction() is called later on. It sends WebPageProxy::DecidePolicyForNavigationAction IPC to the UIProcess with a navigationID that is 0 (instead of the actual navigationID of the BackForward Navigation object)
6. WebPageProxy::decidePolicyForNavigationAction() is called and since navigationID is 0, it constructors a new Navigation object by calling m_navigationState->createLoadRequestNavigation().

Later on, when navigating away, the LoadRequestNavigation object will be destroyed. However, the BackForwardNavigation object will be leaked.

--
Related to <rdar://problem/21305706> but likely a different reason for leaking.

[Chris Dumez]

Created attachment 254833 [details]
WIP Patch

Upload WIP patch in case Sam / Anders have early feedback. It does fix the leak but I do not know much about those Navigation objects.

[Chris Dumez]

Created attachment 254849 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 254849 [details]
Patch

Clearing flags on attachment: 254849

Committed r185542: <http://trac.webkit.org/changeset/185542>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.