InputDevice: return std::optional from getAbsoluteAxisInfo

This also allows us to remove the valid field from RawAbsoluteAxisInfo,
since we can represent "invalid" axes (which usually just meant absent
ones) using std::nullopt.

Test: atest inputflinger_tests
Test: m checkinput
Test: Check "Raw Touch Axes" section of touch input mapper info in
      dumpsys input
Bug: 245989146
Flag: EXEMPT refactor
Change-Id: I045a2e0b61a84657f2f8171c1fee3cc3e331ac86
diff --git a/services/inputflinger/reader/mapper/TouchInputMapper.h b/services/inputflinger/reader/mapper/TouchInputMapper.h
index 30c58a5..beab6e7 100644
--- a/services/inputflinger/reader/mapper/TouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/TouchInputMapper.h
@@ -61,17 +61,17 @@
 struct RawPointerAxes {
     RawAbsoluteAxisInfo x{};
     RawAbsoluteAxisInfo y{};
-    RawAbsoluteAxisInfo pressure{};
-    RawAbsoluteAxisInfo touchMajor{};
-    RawAbsoluteAxisInfo touchMinor{};
-    RawAbsoluteAxisInfo toolMajor{};
-    RawAbsoluteAxisInfo toolMinor{};
-    RawAbsoluteAxisInfo orientation{};
-    RawAbsoluteAxisInfo distance{};
-    RawAbsoluteAxisInfo tiltX{};
-    RawAbsoluteAxisInfo tiltY{};
-    RawAbsoluteAxisInfo trackingId{};
-    RawAbsoluteAxisInfo slot{};
+    std::optional<RawAbsoluteAxisInfo> pressure{};
+    std::optional<RawAbsoluteAxisInfo> touchMajor{};
+    std::optional<RawAbsoluteAxisInfo> touchMinor{};
+    std::optional<RawAbsoluteAxisInfo> toolMajor{};
+    std::optional<RawAbsoluteAxisInfo> toolMinor{};
+    std::optional<RawAbsoluteAxisInfo> orientation{};
+    std::optional<RawAbsoluteAxisInfo> distance{};
+    std::optional<RawAbsoluteAxisInfo> tiltX{};
+    std::optional<RawAbsoluteAxisInfo> tiltY{};
+    std::optional<RawAbsoluteAxisInfo> trackingId{};
+    std::optional<RawAbsoluteAxisInfo> slot{};
 
     inline int32_t getRawWidth() const { return x.maxValue - x.minValue + 1; }
     inline int32_t getRawHeight() const { return y.maxValue - y.minValue + 1; }