Dependency injection for apu/gpu/hid.

src/xenia/gpu/trace_viewer.cc

@@ -66,7 +66,9 @@ bool TraceViewer::Setup() {
 
   // Create the emulator but don't initialize so we can setup the window.
   emulator_ = std::make_unique<Emulator>(L"");
-  X_STATUS result = emulator_->Setup(window_.get());
+  X_STATUS result =
+      emulator_->Setup(window_.get(), nullptr,
+                       [this]() { return CreateGraphicsSystem(); }, nullptr);
   if (XFAILED(result)) {
     XELOGE("Failed to setup emulator: %.8X", result);
     return false;