Bug 902591 - Choose the number of linear gradient repetitions in such a way that the whole extents rect is filled. Substantial parts of the code in this patch were written by roc in bug 508730. r=mattwoodrow

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extra : rebase_source : d7f99adc56ef4d81e14bf3ece6761dd8d5c476ed
Bug 923650 - Restore scissor rects in CompositorOGL more diligently. r=mattwoodrow

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extra : rebase_source : 5a3cccbd38b18aaa8536382ff744a871646ee786