OverlayProperty API implementation

- load overlay properties upon SF callbacks.

Bug: 242588489
Test: atest libsurfaceflinger_unittest, hardcode some dataspaces and
pixelformats values in HalImpl::getOverlaySupport to make sure the path
from HWC to HWUI is functionally workable on the device

Change-Id: I7e5ab7e242ca86daa991141910690f633c5de6ac
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index a9337d8..e264570 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -334,9 +334,9 @@
     return Error::NONE;
 }
 
-Error Display::getOverlaySupport(OverlayProperties* /*outProperties*/) const {
-    // TODO(b/242588489): implement details
-    return Error::NONE;
+Error Display::getOverlaySupport(OverlayProperties* outProperties) const {
+    auto intError = mComposer.getOverlaySupport(outProperties);
+    return static_cast<Error>(intError);
 }
 
 Error Display::getDisplayedContentSamplingAttributes(hal::PixelFormat* outFormat,