Add support for the Rec601 YUV color space to GrYUVtoRGBEffect.

src/gpu/effects/GrYUVtoRGBEffect.h

Index: src/gpu/effects/GrYUVtoRGBEffect.h
diff --git a/src/gpu/effects/GrYUVtoRGBEffect.h b/src/gpu/effects/GrYUVtoRGBEffect.h
index 150acd5a9027a553fac11d5a3a5813208a9333fa..7f406431f7f16eacd24c573e91023faff19c9f13 100644
--- a/src/gpu/effects/GrYUVtoRGBEffect.h
+++ b/src/gpu/effects/GrYUVtoRGBEffect.h
@@ -12,10 +12,19 @@ class GrEffect;
 class GrTexture;
 
 namespace GrYUVtoRGBEffect {
+    enum YUVColorSpace {

[rileya (GONE FROM CHROMIUM), 2014/08/28 01:03:28]

Is there a better place for this enum to live?

[bsalomon, 2014/08/28 13:33:26]

Not sure about whether there is a more natural place, but the enum values should
be suffixed with "_YUVColorSpace".

+        /** Standard JPEG color space. */
+        kJPEG,

[Stephen White, 2014/08/28 15:11:06]

This should be kJPEG_YUVColorSpace according to Skia coding style.

Maybe we should just call it ColorSpace, since the YUV is implied by the scoping
class? It would make the enum values a little less ungainly.

Out of curiosity, will we need Rec.709 as well? The coefficients are slightly
different for HD video (for reasons that escape me).

[rileya (GONE FROM CHROMIUM), 2014/08/28 21:05:57]

Yeah, in the long term rec709 should be supported. However, none of the existing
YUV paths in chromium actually support it yet, so that'll need to be a separate
effort that touches cc/, libyuv, etc.

+        /** SDTV standard Rec. 601 color space. Uses "studio swing" [16, 235] color
+           range. See http://en.wikipedia.org/wiki/Rec._601 for details. */
+        kRec601
+    };
+
     /**
      * Creates an effect that performs color conversion from YUV to RGB
      */
-    GrEffect* Create(GrTexture* yTexture, GrTexture* uTexture, GrTexture* vTexture);
+    GrEffect* Create(GrTexture* yTexture, GrTexture* uTexture, GrTexture* vTexture,
+                     YUVColorSpace type);
 };
 
 #endif