Add capability for SkColorXform to output half floats

dm/DMSrcSink.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef DMSrcSink_DEFINED
 #define DMSrcSink_DEFINED
 
@@ skipping 207 matching lines @@
         kDst_HPZR30w_Mode,
 
         kDst_sRGB_Mode,
 
 #if defined(SK_TEST_QCMS)
         // Use QCMS for color correction.
         kQCMS_HPZR30w_Mode,
 #endif
     };
 
-    ColorCodecSrc(Path, Mode);
+    ColorCodecSrc(Path, Mode, SkColorType);
 
     Error draw(SkCanvas*) const override;
     SkISize size() const override;
     Name name() const override;
     bool veto(SinkFlags) const override;
 private:
     Path                    fPath;
     Mode                    fMode;
+    SkColorType             fColorType;
 };
 
 class SKPSrc : public Src {
 public:
     explicit SKPSrc(Path path);
 
     Error draw(SkCanvas*) const override;
     SkISize size() const override;
     Name name() const override;
 private:
@@ skipping 179 matching lines @@
 
 class ViaMojo : public Via {
 public:
     explicit ViaMojo(Sink* sink) : Via(sink) {}
     Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const override;
 };
 
 }  // namespace DM
 
 #endif//DMSrcSink_DEFINED