Hide (mostly) unused SkColorSpace writeToICC() function

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 95 matching lines @@
                                                              srgbToxyzD50);
     REPORTER_ASSERT(r, rgbColorSpace == namedColorSpace);
 
     // Change a single value from the sRGB matrix
     srgbToxyzD50.set(2, 2, 0.5f);
     sk_sp<SkColorSpace> strangeColorSpace = SkColorSpace::NewRGB(SkColorSpace::kSRGB_GammaNamed,
                                                                  srgbToxyzD50);
     REPORTER_ASSERT(r, strangeColorSpace != namedColorSpace);
 }
 
+class ColorSpaceTest {
+public:
+    static sk_sp<SkData> WriteToICC(SkColorSpace* space) {
+        return as_CSB(space)->writeToICC();
+    }
+};
+
 DEF_TEST(ColorSpaceWriteICC, r) {
     // Test writing a new ICC profile
     sk_sp<SkColorSpace> namedColorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
-    sk_sp<SkData> namedData = as_CSB(namedColorSpace)->writeToICC();
+    sk_sp<SkData> namedData = ColorSpaceTest::WriteToICC(namedColorSpace.get());
     sk_sp<SkColorSpace> iccColorSpace = SkColorSpace::NewICC(namedData->data(), namedData->size());
     test_space(r, iccColorSpace.get(), g_sRGB_XYZ, &g_sRGB_XYZ[3], &g_sRGB_XYZ[6],
                SkColorSpace::k2Dot2Curve_GammaNamed);
     // FIXME (msarett): Test disabled.  sRGB profiles are written approximately as 2.2f curves.
     // REPORTER_ASSERT(r, iccColorSpace == namedColorSpace);
 
     // Test saving the original ICC data
     sk_sp<SkData> monitorData = SkData::MakeFromFileName(
             GetResourcePath("icc_profiles/HP_ZR30w.icc").c_str());
     REPORTER_ASSERT(r, monitorData);
     if (!monitorData) {
         return;
     }
     sk_sp<SkColorSpace> monitorSpace = SkColorSpace::NewICC(monitorData->data(),
                                                             monitorData->size());
-    sk_sp<SkData> newMonitorData = as_CSB(monitorSpace)->writeToICC();
+    sk_sp<SkData> newMonitorData = ColorSpaceTest::WriteToICC(monitorSpace.get());
     sk_sp<SkColorSpace> newMonitorSpace = SkColorSpace::NewICC(newMonitorData->data(),
                                                                newMonitorData->size());
     REPORTER_ASSERT(r, monitorSpace->xyz() == newMonitorSpace->xyz());
     REPORTER_ASSERT(r, monitorSpace->gammaNamed() == newMonitorSpace->gammaNamed());
 }
 
 DEF_TEST(ColorSpace_Named, r) {
     const struct {
         SkColorSpace::Named fNamed;
         bool fExpectedToSucceed;
@@ skipping 99 matching lines @@
     REPORTER_ASSERT(r, !SkColorSpace::Equals(nullptr, srgb.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(srgb.get(), nullptr));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(adobe.get(), srgb.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(z30.get(), srgb.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(z32.get(), z30.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(upperLeft.get(), srgb.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(upperLeft.get(), upperRight.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(z30.get(), upperRight.get()));
     REPORTER_ASSERT(r, !SkColorSpace::Equals(upperRight.get(), adobe.get()));
 }