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/tests/TestConfigParsing.cpp b/tests/TestConfigParsing.cpp
index 9675eed..70fe0e2 100644
--- a/tests/TestConfigParsing.cpp
+++ b/tests/TestConfigParsing.cpp
@@ -86,7 +86,7 @@
     SkCommandLineConfigArray configs;
     ParseConfigs(config1, &configs);
 
-    auto srgbColorSpace = SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named);
+    auto srgbColorSpace = SkColorSpace::MakeSRGB();
 
     REPORTER_ASSERT(reporter, configs.count() == config1.count());
     for (int i = 0; i < config1.count(); ++i) {