SF: Deduplicate FakeDisplayInjector

Also, parametrize to inject secondary internal display.

Bug: 241285876
Test: libsurfaceflinger_unittest
Change-Id: I63d21c2216a3ab864b040bdb2c9e8fba0768b66a
diff --git a/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h b/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h
index 9cceb5e..19c7d5c 100644
--- a/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h
+++ b/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h
@@ -42,6 +42,7 @@
 #include <renderengine/mock/RenderEngine.h>
 #include <ui/DebugUtils.h>
 
+#include "FakeDisplayInjector.h"
 #include "TestableScheduler.h"
 #include "TestableSurfaceFlinger.h"
 #include "mock/DisplayHardware/MockComposer.h"
@@ -88,8 +89,11 @@
     void injectMockComposer(int virtualDisplayCount);
     void injectFakeBufferQueueFactory();
     void injectFakeNativeWindowSurfaceFactory();
+
     sp<DisplayDevice> injectDefaultInternalDisplay(
-            std::function<void(TestableSurfaceFlinger::FakeDisplayDeviceInjector&)>);
+            std::function<void(TestableSurfaceFlinger::FakeDisplayDeviceInjector&)> injectExtra) {
+        return mFakeDisplayInjector.injectInternalDisplay(injectExtra);
+    }
 
     // --------------------------------------------------------------------
     // Postcondition helpers
@@ -114,6 +118,8 @@
     sp<GraphicBuffer> mBuffer = sp<GraphicBuffer>::make();
     Hwc2::mock::PowerAdvisor mPowerAdvisor;
 
+    FakeDisplayInjector mFakeDisplayInjector{mFlinger, mPowerAdvisor, mNativeWindow};
+
     // These mocks are created by the test, but are destroyed by SurfaceFlinger
     // by virtue of being stored into a std::unique_ptr. However we still need
     // to keep a reference to them for use in setting up call expectations.