Handle DISPLAY_DECORATION

I90543850d57323be485a0fa8562f4e965aed28ab in hardware/interfaces
introduces the new Composition type, DISPLAY_DECORATION. Handle this
case when looking at Composition.

Bug: 193170859
Test: TODO
Change-Id: Ic5d5881dbbbaa348bf5ba39c5f8a4fca7b7170b4
diff --git a/services/surfaceflinger/DisplayHardware/Hal.h b/services/surfaceflinger/DisplayHardware/Hal.h
index 77e704f..7236868 100644
--- a/services/surfaceflinger/DisplayHardware/Hal.h
+++ b/services/surfaceflinger/DisplayHardware/Hal.h
@@ -111,6 +111,8 @@
             return "Cursor";
         case aidl::android::hardware::graphics::composer3::Composition::SIDEBAND:
             return "Sideband";
+        case aidl::android::hardware::graphics::composer3::Composition::DISPLAY_DECORATION:
+            return "DisplayDecoration";
         default:
             return "Unknown";
     }