Fix decoding RAW images to 565

Bug: skia:8473

Follow-on to 96765960dc505a722e05fcdf974b363bfff47f11.

In SkRawCodec, call select_xform_format (in SkCodec.cpp, now shared
via SkCodecPriv.h) to determine the destination skcms_PixelFormat
for the color transform. This switches kRGB_565_SkColorType decodes
from skcms_PixelFormat_RGB_565 to skcms_PixelFormat_BGR_565, which
fixes some broken images in Gold.

Change-Id: I38eebc06610c7ec8898453ae7a9df7e1ed04efa6
Reviewed-on: https://skia-review.googlesource.com/c/175992
Commit-Queue: Leon Scroggins <scroggo@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
3 files changed