Bug 1003893 - Ensure that the delete of RasterImage occurs on the main thread. r=seth

Dispatch nsRefPtr<RasterImage> to the main thread by NS_ProxyRelease
to avoid RasterImage from being destructed by the DecodeJob thread.
(If gMultithreadedDecoding is true.)
Therefore, DiscardTracker can safely access RasterImage::Discard()
by the raw pointer in DiscardTracker::Node.
Bug 1020122 - IonMonkey: (ARM) Remove some unused arguments on internal assembler methods. r=mjrosenb
Bug 1021309 - Add "mac-yosemite-theme" CSS system metric. r=mstange
Bug 1024090 - Ensure proper loading of Notification database. r=gwagner
Bug 1025874 - Fix widget->style access on gtk3. r=karlt