Bug 1094442 - Part 1: Refactor how tile w/h is queried r=kats

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extra : rebase_source : 70ef00318a718e2ce3149955d2908615d6125cf3
Bug 1094442 - Part 2: Adjust tile size to the stride of the gralloc buffers. r=kats

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extra : rebase_source : d3386ee007d6429b81aa6d3ffe6c518fb67c7d6a