Bug 878935, Part 1: Add a "freeze" counter to nsRefreshDriver to keep track of how many times it was frozen. r=dbaron

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extra : rebase_source : 135e5d52fc7fe38bdf57ca2d103ff372d9011873
Bug 878935, Part 2: Pause painting while reflow-on-zoom is in progress to provide a better user experience. r=kats,dbaron

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extra : rebase_source : 7eb13d00208cef8e696ec6e9a1cdc2739a994d9a