Do not merge.

Backport changes related to BitmapRegionDecoder from HoneyComb to
Gingerbread.

Bug: 3309014

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This is a combination of 7 commits.
Revert "Do not merge."

This reverts commit f7681f84.

Change-Id: I46fd710600b1649773eaea2d9abc2b21a592f9a6

Fix a initialization bug in BitmapRegionDecoder.

Change-Id: I6c1151fd34970a84d4de52d664d9a5dc464892c5

Fix segfault when tring to throw IOException.

Change-Id: I530cc4409ba4ca17cec933afad077c5f60ba554f

Fix 3122139, where previewing an attachment for the second time will
fail.

Use AutoFDSeek to mark and restore the position before we read data from
the descriptor.

Change-Id: I3d4f012dce486e19b113bc90a98b94031cfa8195

Add inPreferQualityOverSpeed into BitmapFactory.Options.

The new field allows a developer to use a more accurate by
slightly slower IDCT method in JPEG decode. This in turns improves the
quality of the reconstructed image.

The field by default is not set and thus does not affect existing
applications.

Bug: 3238925
Change-Id: I93d55b7226e47a43e639325cd1a677694d6f2ee4

Unhide inPreferQualityOverSpeed in BitmapFactory.Options.

The new field allows a developer to use a more accurate by
slightly slower IDCT method in JPEG decode. This in turns improves the
quality of the reconstructed image.

The field by default is not set and thus does not affect existing
applications.

Bug: 3238925

Related changes: https://android-git.corp.google.com/g/#change,83291 and
                 https://android-git.corp.google.com/g/#change,83294

Change-Id: I969f5c413f9b2179454aeb90e18ae8222ee583b4

Correct the API comments.

BitmapRegionDecoder supports PNG as well.