We mistakenly used to take a snapshot and compress it when we started a swipe animation and again when we were just about to navigate away from the current page. This separates the two steps of snapshotting and compression and only does them once per animation.

Updated to apply over new patches in bug 836430. Carrying over r+.

Updated to apply over new patches in bug 836430. Carrying over r?.

Sent to try, along with the patches in bug 836430: https://tbpl.mozilla.org/?tree=Try&rev=006bb18afe21

b-c tests failed in the try run. :mikedeboer was kind enough to point out to me that I forgot about the early return at the beginning of 'HSA__takeSnapshot'. When a tab first opens, the history index is -1 which would lead to an early return and leave gBrowser.selectedBrowser.snapshots uninitialized. However, we would then try to retrieve it in 'HSA__compressSnapshotAtCurrentIndex', which leads to the errors in b-c. This patch here is green on try: https://tbpl.mozilla.org/?tree=Try&rev=a8d1dcbc78f0

Updated for new patch. Setting back to r?.

https://hg.mozilla.org/integration/mozilla-inbound/rev/7ecbe700f096 https://hg.mozilla.org/integration/mozilla-inbound/rev/34ffe646812e

https://hg.mozilla.org/mozilla-central/rev/7ecbe700f096 https://hg.mozilla.org/mozilla-central/rev/34ffe646812e