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

Merged-In: I2b0a92196a8a1f05f7d99b531775b9979f07af98
Change-Id: I2b0a92196a8a1f05f7d99b531775b9979f07af98
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 380f444..fa19b7f 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -614,6 +614,7 @@
     sp<IBinder> createDisplay(const String8& displayName, bool secure) override;
     void destroyDisplay(const sp<IBinder>& displayToken) override;
     std::vector<PhysicalDisplayId> getPhysicalDisplayIds() const override;
+    status_t getPrimaryPhysicalDisplayId(PhysicalDisplayId*) const override EXCLUDES(mStateLock);
     sp<IBinder> getPhysicalDisplayToken(PhysicalDisplayId displayId) const override;
     status_t setTransactionState(const FrameTimelineInfo& frameTimelineInfo,
                                  const Vector<ComposerState>& state,