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/gm/all_bitmap_configs.cpp b/gm/all_bitmap_configs.cpp
index e954fc3..227c387 100644
--- a/gm/all_bitmap_configs.cpp
+++ b/gm/all_bitmap_configs.cpp
@@ -266,7 +266,7 @@
     sk_tool_utils::draw_checkerboard(canvas, SK_ColorLTGRAY, SK_ColorWHITE, 8);
 
     sk_sp<SkColorSpace> colorSpaces[] {
-        SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named),
+        SkColorSpace::MakeSRGB(),
         nullptr,
     };
     for (auto colorSpace : colorSpaces) {