Allow decoding without color conversion

Bug: b/135133301

Especially for the Android NDK, which may not be able to report the
default profile, we should be able to decode the image without doing
any color correction. That way if the client wants to figure out
the color profile on their own (e.g. by parsing the data manually),
they can retrieve the un-corrected pixels and treat them appropriately.

Note that internally, we still require a destination profile for F16,
but we will use the source profile if there is one, or SRGB for source
and destination otherwise. Regardless, this will result in no color
correction.

Change-Id: Id1157bb99d3119a114b25f64b38620480a027f34
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268157
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index 66f6580..f10c3f1 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -7,6 +7,9 @@
 Milestone 82
 
 <Insert new notes here- top is most recent.>
+  * An SkImageInfo with a null SkColorSpace passed to SkCodec::getPixels() and
+    related calls is treated as a request to do no color correction at decode
+    time.
 
   * Remove CGFontRef parameter from SkCreateTypefaceFromCTFont.
     Use CTFontManagerCreateFontDescriptorFromData instead of