add MakeS32 helper to SkImageInfo, fix named-gamma constructor bug

tests/ColorSpaceTest.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkCodec.h"
 #include "SkColorSpace.h"
@@ skipping 120 matching lines @@
         return;
     }
     sk_sp<SkColorSpace> monitorSpace = SkColorSpace::NewICC(monitorData->data(),
                                                             monitorData->size());
     sk_sp<SkData> newMonitorData = as_CSB(monitorSpace)->writeToICC();
     sk_sp<SkColorSpace> newMonitorSpace = SkColorSpace::NewICC(newMonitorData->data(),
                                                                newMonitorData->size());
     REPORTER_ASSERT(r, monitorSpace->xyz() == newMonitorSpace->xyz());
     REPORTER_ASSERT(r, as_CSB(monitorSpace)->gammas() == as_CSB(newMonitorSpace)->gammas());
 }
+
+DEF_TEST(ColorSpace_Named, r) {
+    const struct {
+        SkColorSpace::Named fNamed;
+        bool fExpectedToSucceed;
+    } recs[] {
+        { SkColorSpace::kUnknown_Named,  false },
+        { SkColorSpace::kSRGB_Named,     true  },
+        { SkColorSpace::kAdobeRGB_Named, true  },
+    };
+
+    for (auto rec : recs) {
+        auto cs = SkColorSpace::NewNamed(rec.fNamed);
+        REPORTER_ASSERT(r, !cs == !rec.fExpectedToSucceed);
+        if (cs) {
+            REPORTER_ASSERT(r, SkColorSpace::k2Dot2Curve_GammaNamed == cs->gammaNamed());
+        }
+    }
+
+    SkImageInfo info = SkImageInfo::MakeS32(10, 10, kPremul_SkAlphaType);
+    REPORTER_ASSERT(r, kSRGB_SkColorProfileType == info.profileType());
+    REPORTER_ASSERT(r, SkColorSpace::k2Dot2Curve_GammaNamed == info.colorSpace()->gammaNamed());
+}