Make SkCodec truly default to sRGB

Remove SkEncodedInfo::ICCProfile::MakeSRGB. Instead of creating
this object whenever there is no encoded color profile, just
treat null as sRGB, like skcms does.

This may help with crbug.com/887372. Regardless it simplifies the
code.

Also fix a bug where SkCodec could have passed a null
skcms_ICCProfile to skcms_ApproximatelyEqualProfiles (related
to b/116608007).

Bug: chromium:887372
Change-Id: I2374e8d8a1aed261f1291b7f6fd6c7ea662f26fd
Reviewed-on: https://skia-review.googlesource.com/157561
Auto-Submit: Leon Scroggins <scroggo@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index 21570fd..926fedf 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -282,9 +282,7 @@
 
 std::unique_ptr<SkCodec> SkJpegCodec::MakeFromStream(std::unique_ptr<SkStream> stream,
                                                      Result* result) {
-    return SkJpegCodec::MakeFromStream(std::move(stream), result,
-                                       // FIXME: This may not be used. Can we skip creating it?
-                                       SkEncodedInfo::ICCProfile::MakeSRGB());
+    return SkJpegCodec::MakeFromStream(std::move(stream), result, nullptr);
 }
 
 std::unique_ptr<SkCodec> SkJpegCodec::MakeFromStream(std::unique_ptr<SkStream> stream,