XFA: merge patch from CL 826633002, fix windows printing black rectangle issue
XFA: merge patch from CL 826633002, fix windows printing black rectangle issue

In windows printing, convert src bitmap to dest bitmap using CompositeBitmap.

When dealing with transparency, the printing procedure will generate a bitmap first,
then draw this bitmap in windows DC.
The format of source bitmap is argb, but the destination bitmap is rgb.
Simply doing memcpy will lose the alpha channel information, so CompositeBitmap function is needed.

BUG=412908
R=vitalybuka@chromium.org

Review URL: https://codereview.chromium.org/826633002

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