SF: Temporarily expose primary display id

WM needs to know the address of the primary display in order to
consume ro.surface_flinger.primary_display_orientation correctly.
This path will be removed in the future once we support per
display install orientations.

Bug: 196167822
Test: check initial buffer transforms on displays with a different
install orientation

Change-Id: I2b0a92196a8a1f05f7d99b531775b9979f07af98
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index d1ad478..a9f4d09 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -694,6 +694,7 @@
             bool /*secure*/) override { return nullptr; }
     void destroyDisplay(const sp<IBinder>& /*display */) override {}
     std::vector<PhysicalDisplayId> getPhysicalDisplayIds() const override { return {}; }
+    status_t getPrimaryPhysicalDisplayId(PhysicalDisplayId*) const override { return NO_ERROR; }
     sp<IBinder> getPhysicalDisplayToken(PhysicalDisplayId) const override { return nullptr; }
     status_t setTransactionState(const FrameTimelineInfo& /*frameTimelineInfo*/,
                                  const Vector<ComposerState>& /*state*/,