Move displayid into InputEvent

There are certain use cases where key events should be associated with a
particular display. Refactor KeyEvent and MotionEvent to have an
associated display id.

Remove "hasAssociatedDisplay" variable from KeyboardInputMapper,
it just used to mirror "isOrientationAware".

If the keyboard is orientation aware (= it is physically attached to a
display, and therefore rotates together with that display), then
associate that keyboard with the internal viewport. Otherwise, the key
events are not associated with any particular display.

Remaining to do:
- make mInternalDisplay, mExternalDisplay, mVirtualDisplays into a
single vector with type (internal, external, virtual)
- have getDisplayViewport return std::optional (will require deep
changes)

Bug: 64258305
Test: atest inputflinger_tests libinput_tests

Change-Id: I4fe145e74cb59310efaa55bfc9dc3c2b3bd997e3
diff --git a/services/inputflinger/Android.bp b/services/inputflinger/Android.bp
index a9e5a43..45efb9f 100644
--- a/services/inputflinger/Android.bp
+++ b/services/inputflinger/Android.bp
@@ -15,6 +15,8 @@
 cc_library_shared {
     name: "libinputflinger",
 
+    cpp_std: "c++17",
+
     srcs: [
         "EventHub.cpp",
         "InputApplication.cpp",