Add GrColorSpaceInfo and use in place of GrRenderTargetContext in paint conversion.

This moves us closer to making GrAtlasTextContext and related classes usable without a GrRenderTargetContext.

Change-Id: Ife52d69a3f925e23da88043acb4d8dc9f672a025
Reviewed-on: https://skia-review.googlesource.com/63304
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/gn/gpu.gni b/gn/gpu.gni
index 33f6566..8f82e71 100644
--- a/gn/gpu.gni
+++ b/gn/gpu.gni
@@ -65,6 +65,7 @@
   "$_src/gpu/GrClip.h",
   "$_src/gpu/GrClipStackClip.h",
   "$_src/gpu/GrClipStackClip.cpp",
+  "$_src/gpu/GrColorSpaceInfo.cpp",
   "$_src/gpu/GrColorSpaceXform.cpp",
   "$_src/gpu/GrColorSpaceXform.h",
   "$_src/gpu/GrContext.cpp",