start on apply gamma cleanup

tools/viewer/sk_app/WindowContext.cpp

Index: tools/viewer/sk_app/WindowContext.cpp
diff --git a/tools/viewer/sk_app/WindowContext.cpp b/tools/viewer/sk_app/WindowContext.cpp
index 5d364bc497bf8273572480c19af6f035c428f2c2..7c3bae67f08f7c6651123db4c4cf68564986349b 100755
--- a/tools/viewer/sk_app/WindowContext.cpp
+++ b/tools/viewer/sk_app/WindowContext.cpp
@@ -65,6 +65,8 @@ void WindowContext::presentRenderSurface(sk_sp<SkSurface> renderSurface, sk_sp<G
                                          int colorBits) {
     if (!this->isGpuContext() || colorBits > 24 ||
         kRGBA_F16_SkColorType == fDisplayParams.fColorType) {
+        sk_sp<SkImage> image = renderSurface->makeImageSnapshot();
+
         // We made/have an off-screen surface. Get the contents as an SkImage:
         SkImageInfo info = SkImageInfo::Make(fWidth, fHeight,
                                              fDisplayParams.fColorType,