Use Offscreen Surface for Split Screen

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 41bbd14576b37f604c8f65d7001b8de076932553..f438789777eaa48ddddea403cf95da6c05098c1a 100755
--- a/tools/viewer/sk_app/WindowContext.cpp
+++ b/tools/viewer/sk_app/WindowContext.cpp
@@ -21,24 +21,33 @@
 
 namespace sk_app {
 
-sk_sp<SkSurface> WindowContext::createRenderSurface(sk_sp<GrRenderTarget> rt, int colorBits) {
+sk_sp<SkSurface> WindowContext::createRenderSurface(
+        sk_sp<GrRenderTarget> rt, int colorBits, bool offscreen, bool sRGB) {
     auto flags = (fSurfaceProps.flags() & ~SkSurfaceProps::kGammaCorrect_Flag) |
-                 (GrPixelConfigIsSRGB(fPixelConfig) ? SkSurfaceProps::kGammaCorrect_Flag : 0);
+                 (GrPixelConfigIsSRGB(fPixelConfig) || sRGB ?
+                  SkSurfaceProps::kGammaCorrect_Flag : 0);
     SkSurfaceProps props(flags, fSurfaceProps.pixelGeometry());
 
-    if (!this->isGpuContext() || colorBits > 24 ||
+    if (!this->isGpuContext() || colorBits > 24 || offscreen ||
         kRGBA_F16_SkColorType == fDisplayParams.fColorType) {
         // If we're rendering to F16, we need an off-screen surface - the current render
         // target is most likely the wrong format.
         //
         // If we're rendering raster data or using a deep (10-bit or higher) surface, we probably
         // need an off-screen surface. 10-bit, in particular, has strange gamma behavior.
-        SkImageInfo info = SkImageInfo::Make(fWidth, fHeight,
-                                             fDisplayParams.fColorType,
-                                             kUnknown_SkAlphaType,
-                                             fDisplayParams.fProfileType);
-        return SkSurface::MakeRenderTarget(fContext, SkBudgeted::kNo, info,
-                                           fDisplayParams.fMSAASampleCount, &props);
+        SkImageInfo info = SkImageInfo::Make(
+                fWidth, fHeight,
+                fDisplayParams.fColorType,
+                kPremul_SkAlphaType,
+                (sRGB || fDisplayParams.fProfileType == kSRGB_SkColorProfileType) ?
+                    SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named) : nullptr
+        );
+        if (this->isGpuContext()) {
+            return SkSurface::MakeRenderTarget(fContext, SkBudgeted::kNo, info,
+                                               fDisplayParams.fMSAASampleCount, &props);
+        } else {
+            return SkSurface::MakeRaster(info, &props);
+        }
     } else {
         return SkSurface::MakeRenderTargetDirect(rt.get(), &props);
     }