Add support for writing ICC profiles in png encodes

BUG=skia:

Change-Id: I99eb2f157f249ed09d724461ec4a1e31db70816a
Reviewed-on: https://skia-review.googlesource.com/9782
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
diff --git a/src/images/SkImageEncoderPriv.h b/src/images/SkImageEncoderPriv.h
index 5f7560d..69d45fb 100644
--- a/src/images/SkImageEncoderPriv.h
+++ b/src/images/SkImageEncoderPriv.h
@@ -11,15 +11,15 @@
 #include "SkImageEncoder.h"
 
 struct SkEncodeOptions {
-    enum class PremulBehavior {
+    enum class ColorBehavior {
          // Convert to a linear space before premultiplying or unpremultiplying.
-        kGammaCorrect,
+        kCorrect,
 
         // Ignore the transfer function when premultiplying or unpremultiplying.
         kLegacy,
     };
 
-    PremulBehavior fPremulBehavior = PremulBehavior::kLegacy;
+    ColorBehavior fColorBehavior = ColorBehavior::kLegacy;
 };
 
 #ifdef SK_HAS_JPEG_LIBRARY