Add capability for SkColorXform to output half floats

tests/ColorSpaceXformTest.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 "SkColorPriv.h"
@@ skipping 27 matching lines @@
             0xFFABCDEF, 0xFF146829, 0xFF382759, 0xFF184968, 0xFFDE8271,
             0xFF32AB52, 0xFF0383BC, 0xFF000102, 0xFFFFFFFF, 0xFFDDEEFF, };
     uint32_t dstPixels[width];
 
     // Identity matrix
     SkMatrix44 srcToDst = SkMatrix44::I();
 
     // Create and perform xform
     std::unique_ptr<SkColorSpaceXform> xform =
             ColorSpaceXformTest::CreateDefaultXform(gammas, srcToDst, gammas);
-    xform->xform_RGB1_8888(dstPixels, srcPixels, width);
+    xform->applyTo8888(dstPixels, srcPixels, width);
 
     // Since the matrix is the identity, and the gamma curves match, the pixels
     // should be unchanged.
     for (int i = 0; i < width; i++) {
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >>  0) & 0xFF),
                                         SkGetPackedR32(dstPixels[i])));
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >>  8) & 0xFF),
                                         SkGetPackedG32(dstPixels[i])));
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >> 16) & 0xFF),
                                         SkGetPackedB32(dstPixels[i])));
@@ skipping 47 matching lines @@
 }
 
 DEF_TEST(ColorSpaceXform_ExponentialGamma, r) {
     // Exponential gamma curves
     SkGammaCurve red, green, blue;
     red.fValue = green.fValue = blue.fValue = 1.4f;
     sk_sp<SkGammas> gammas =
             sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
     test_xform(r, gammas);
 }