Bug 851338 - Implement AudioContext.currentTime; r=roc

Landed on a CLOSED TREE, because I'm mad at X11!
Back out 0044e4c2dc53 (bug 851149), 3080f18ba53d (bug 698328), 0b147c3f682b (bug 850713) for Android bustage
CLOSED TREE
Back out 298a598dde74 (bug 849988) for test_bug_779982.html timeouts
CLOSED TREE
Bug 837011 - CallCompiler should return 'true' because it doesn't throw an exception (r=dvander)

--HG--
extra : rebase_source : 326ad9707d64db437d0a7dddfef9bbffbb59038e
Bug 702504 - Make USE_WIDGET_LAYERS disabled a test failure. r=roc
Bug 676746 - Forcibly initialize the persistant layer manager when we try to read its backend type. r=joe
Bug 841651: Update NSPR to NSPR_4_9_6_RTM. Remove the private patch.
bug 850973 - remove nsAccUtils::IsText() r=surkov
bug 850990 - remove nsAccessNode::IsDocumentNode() r=surkov
Bug 671976 - Fix print preview asserts (r=smaug)
Bug 767669 - 'pref show prefName' should show the pref name next to the pref value. r=jwalker
b=850559 remove unnecessary advanceTimeAndRefresh() usage

--HG--
extra : rebase_source : f27bb748cb9e1732bcf0f16be158d6684a49fd36
b=850128 don't overwrite NSPR_LOG_MODULES r=ted

--HG--
extra : rebase_source : 7bb6fc608f01bd3a3df2d2d7191c7c8e7fa85333
Backed out changeset 6a23d4536079 (bug 851338) because of Android test failures
Bug 850713 - Bump the required NDK version to 9. r=blassey.bugs,mh+mozilla
Bug 698328 - Add a new cubeb backend based on AudioTrack.cpp. r=kinetik
Bug 851149 - Fix cubeb_sndio build after switchable-backends landing.  r=kinetik
Bug 851169: Add (void)-cast to silence GCC "unused" build warning for variable in Telemetry.cpp whose only usage is currently commented out. r=ehsan
Bug 851183: Mark toolkit/components/telemetry/ as FAIL_ON_WARNINGS. r=nfroyd
Bug 850517 - Factor out child window lookup into a helper. r=mrbkap