Some tests around surface creation and snapshotting with color space

samplecode/SampleApp.cpp

Index: samplecode/SampleApp.cpp
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 9e7e651b1c6e91400e78fa1031fdf1f00cb49110..b6b9cde06ca0d43181f2633b2e7b370f54ef5c34 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -1556,9 +1556,12 @@ bool SampleWindow::onEvent(const SkEvent& evt) {
         return true;
     }
     if (SkOSMenu::FindListIndex(evt, "ColorType", &selected)) {
-        auto srgbColorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
+        auto colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
+        if (kRGBA_F16_SkColorType == gConfig[selected].fColorType) {
+            colorSpace = colorSpace->makeLinearGamma();
+        }
         this->setDeviceColorType(gConfig[selected].fColorType,
-                                 gConfig[selected].fSRGB ? srgbColorSpace : nullptr);
+                                 gConfig[selected].fSRGB ? colorSpace : nullptr);
         return true;
     }
     if (SkOSMenu::FindSwitchState(evt, "Slide Show", nullptr)) {