SkColorSpace: remove named API, add gamut API

Reland from: https://skia-review.googlesource.com/c/8021/

BUG=skia:

Change-Id: I18985f130587b15fccbc86b76b2bb5c49ba5ba8a
Reviewed-on: https://skia-review.googlesource.com/8136
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
diff --git a/src/codec/SkBmpCodec.cpp b/src/codec/SkBmpCodec.cpp
index 66ad0ca..cd46a54 100644
--- a/src/codec/SkBmpCodec.cpp
+++ b/src/codec/SkBmpCodec.cpp
@@ -593,7 +593,7 @@
 
 SkBmpCodec::SkBmpCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream,
         uint16_t bitsPerPixel, SkCodec::SkScanlineOrder rowOrder)
-    : INHERITED(width, height, info, stream, SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named))
+    : INHERITED(width, height, info, stream, SkColorSpace::MakeSRGB())
     , fBitsPerPixel(bitsPerPixel)
     , fRowOrder(rowOrder)
     , fSrcRowBytes(SkAlign4(compute_row_bytes(width, fBitsPerPixel)))