Added --deepColor option to SampleApp, triggers creation of a ten-bit/channel buffer on Windows.

src/views/SkWindow.cpp

Index: src/views/SkWindow.cpp
diff --git a/src/views/SkWindow.cpp b/src/views/SkWindow.cpp
index 244bc4974219b44f4c42218cdfa1ec4f90c6cd3d..d06d6bb9eb4a3b6bf250f7f2946b51239ea83ae9 100644
--- a/src/views/SkWindow.cpp
+++ b/src/views/SkWindow.cpp
@@ -340,9 +340,14 @@ GrRenderTarget* SkWindow::renderTarget(const AttachmentInfo& attachmentInfo,
     //
     // Also, we may not have real sRGB support (ANGLE, in particular), so check for
     // that, and fall back to L32:
-    desc.fConfig = grContext->caps()->srgbSupport() && SkImageInfoIsGammaCorrect(info())
-        ? kSkiaGamma8888_GrPixelConfig
-        : kSkia8888_GrPixelConfig;
+    //
+    // ... and, if we're using a 10-bit/channel FB0, it doesn't do sRGB conversion on write,
+    // so pretend that it's non-sRGB 8888:
+    desc.fConfig =
+        grContext->caps()->srgbSupport() &&
+        SkImageInfoIsGammaCorrect(info()) &&
+        (attachmentInfo.fColorBits != 30)
+        ? kSkiaGamma8888_GrPixelConfig : kSkia8888_GrPixelConfig;
     desc.fOrigin = kBottomLeft_GrSurfaceOrigin;
     desc.fSampleCnt = attachmentInfo.fSampleCount;
     desc.fStencilBits = attachmentInfo.fStencilBits;