Both the ScrollingCoordinator's m_stateNodeMap and ScrollingTree's m_nodeMap get larger and larger as you navigate between pages.
Created attachment 187441 [details]
This patch depends on the patch in bug 109361, so will probably fail EWS.
The changelog should say that this isn't testable, because we only dump the state node tree (which is OK), not the hash map. The scrolling node tree does accumulate extra children, but we don't dump that.
*** Bug 108732 has been marked as a duplicate of this bug. ***