Do color correction of vertex colors in GPU drawVertices

SkColor vertex colors need to be linearized (from sRGB),
and possibly converted from sRGB gamut to destination gamut.

Bug: skia:6659
Change-Id: I2b1b1dd0fa5938519693f56a728fed5957f13fd5
Reviewed-on: https://skia-review.googlesource.com/17534
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrRenderTargetContext.cpp b/src/gpu/GrRenderTargetContext.cpp
index 7d18448..1574fc5 100644
--- a/src/gpu/GrRenderTargetContext.cpp
+++ b/src/gpu/GrRenderTargetContext.cpp
@@ -848,6 +848,8 @@
     SkASSERT(vertices);
     std::unique_ptr<GrLegacyMeshDrawOp> op = GrDrawVerticesOp::Make(paint.getColor(),
                                                                     std::move(vertices), viewMatrix,
+                                                                    this->isGammaCorrect(),
+                                                                    fColorXformFromSRGB,
                                                                     overridePrimType);
     if (!op) {
         return;