Allow GPU composition to occur at a lower resolution

Add a vendor-specified system property to allow GPU fallback composition to occur at a lower resolution than the display mode resolution.

Bug: 144574809

Test: Tested with sysprop disabled, and tested backport in Android Q with sysprop enabled. Unable to test on Android R due to device issues.

Change-Id: I02948ce72f49d20416d0e4dd45a4cffe99e28820
diff --git a/services/surfaceflinger/SurfaceFlingerProperties.h b/services/surfaceflinger/SurfaceFlingerProperties.h
index 12c711a..c63adfe 100644
--- a/services/surfaceflinger/SurfaceFlingerProperties.h
+++ b/services/surfaceflinger/SurfaceFlingerProperties.h
@@ -37,6 +37,9 @@
 
 int64_t max_frame_buffer_acquired_buffers(int64_t defaultValue);
 
+int32_t max_graphics_width(int32_t defaultValue);
+int32_t max_graphics_height(int32_t defaultValue);
+
 bool has_wide_color_display(bool defaultValue);
 
 bool running_without_sync_framework(bool defaultValue);