Fix debugger build by specifying nullptr for color space.

debugger/QT/SkGLWidget.cpp

Index: debugger/QT/SkGLWidget.cpp
diff --git a/debugger/QT/SkGLWidget.cpp b/debugger/QT/SkGLWidget.cpp
index 975052f57d4f6bc63adbf5b2ce38c8fe57dfa116..57cb49dc6f19c2c43e64a29535ac79d566f1d722 100644
--- a/debugger/QT/SkGLWidget.cpp
+++ b/debugger/QT/SkGLWidget.cpp
@@ -63,7 +63,7 @@ void SkGLWidget::createRenderTarget() {
     sk_sp<GrRenderTarget> curRenderTarget(
             fCurContext->textureProvider()->wrapBackendRenderTarget(desc));
     SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
-    fGpuDevice.reset(SkGpuDevice::Make(std::move(curRenderTarget), &props,
+    fGpuDevice.reset(SkGpuDevice::Make(std::move(curRenderTarget), nullptr, &props,
                                        SkGpuDevice::kUninit_InitContents).release());
     fCanvas.reset(new SkCanvas(fGpuDevice));
 }