Improve color space support in SkImage::readPixels()

Correct handling of kGray, k565, k4444 etc. is still a TODO.
SkImage_Generator and SkImage_Gpu are still TODOs.

BUG=skia:6021

Change-Id: Ib53d97d3a866b2b4934fd85c10100855743a8fab
Reviewed-on: https://skia-review.googlesource.com/6396
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/src/codec/SkCodecPriv.h b/src/codec/SkCodecPriv.h
index 75fbcf2..110cbdc 100644
--- a/src/codec/SkCodecPriv.h
+++ b/src/codec/SkCodecPriv.h
@@ -10,6 +10,7 @@
 
 #include "SkColorPriv.h"
 #include "SkColorSpaceXform.h"
+#include "SkColorSpaceXformPriv.h"
 #include "SkColorTable.h"
 #include "SkEncodedInfo.h"
 #include "SkImageInfo.h"
@@ -115,26 +116,6 @@
      return nullptr != colorTable ? colorTable->readColors() : nullptr;
 }
 
-static inline SkColorSpaceXform::ColorFormat select_xform_format(SkColorType colorType) {
-    switch (colorType) {
-        case kRGBA_8888_SkColorType:
-            return SkColorSpaceXform::kRGBA_8888_ColorFormat;
-        case kBGRA_8888_SkColorType:
-            return SkColorSpaceXform::kBGRA_8888_ColorFormat;
-        case kRGBA_F16_SkColorType:
-            return SkColorSpaceXform::kRGBA_F16_ColorFormat;
-        case kIndex_8_SkColorType:
-#ifdef SK_PMCOLOR_IS_RGBA
-            return SkColorSpaceXform::kRGBA_8888_ColorFormat;
-#else
-            return SkColorSpaceXform::kBGRA_8888_ColorFormat;
-#endif
-        default:
-            SkASSERT(false);
-            return SkColorSpaceXform::kRGBA_8888_ColorFormat;
-    }
-}
-
 /*
  * Given that the encoded image uses a color table, return the fill value
  */