Bug 1034345 (Part 1) - Add OptimalImageSizeForDest to the imgIContainer interface. r=tn,sr=bz

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extra : rebase_source : 4f73f42647c98f3bde33e46aa81006b14b9bef45
Bug 1034345 (Part 2) - Implement OptimalImageSizeForDest for RasterImage. r=tn

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extra : rebase_source : 63c58e8df2c992f9550b481530e41938e8672ad1
Bug 1034345 (Part 3) - Implement OptimalImageSizeForDest for VectorImage. r=dholbert

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extra : rebase_source : 664f6a978ea69c438535900531c39e23f505e764
Bug 1034345 (Part 4) - Implement OptimalImageSizeForDest for other image types. r=tn

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extra : rebase_source : 3237d5ec3e196ec674d9ab0e67b65b867f458251