Add flag info to displays dump output proto

FLAG_PRIVATE information is needed for cts on physical private display

Bug: 133794475
Test: -Build and flash (make -j framework; aae flash 1s)
- Add "Log.d(TAG, display.toString())" in code to print out detailed
information about display. (Note: Display class is imported from
android.server.wm.WindowManagerState.Display)
- Check "mFlags=.." is printed

Change-Id: I6481dff51b140d3a9320e1e92b06fff531ba34e9

core/java/android/view/DisplayInfo.java

@@ -18,6 +18,7 @@ package android.view;
 
 import static android.view.DisplayInfoProto.APP_HEIGHT;
 import static android.view.DisplayInfoProto.APP_WIDTH;
+import static android.view.DisplayInfoProto.FLAGS;
 import static android.view.DisplayInfoProto.LOGICAL_HEIGHT;
 import static android.view.DisplayInfoProto.LOGICAL_WIDTH;
 import static android.view.DisplayInfoProto.NAME;
@@ -708,6 +709,7 @@ public final class DisplayInfo implements Parcelable {
         protoOutputStream.write(APP_WIDTH, appWidth);
         protoOutputStream.write(APP_HEIGHT, appHeight);
         protoOutputStream.write(NAME, name);
+        protoOutputStream.write(FLAGS, flags);
         protoOutputStream.end(token);
     }
 

core/proto/android/view/displayinfo.proto

@@ -33,4 +33,5 @@ message DisplayInfoProto {
     // The human-readable name of the display.
     // Eg: "Built-in Screen"
     optional string name = 5;
+    optional int32 flags = 6;
 }