TouchpadInputMapper: support touchpad capture

This allows an app to capture the touchpad and receive "raw" touch
information from it. Since some specifics (such as how size is
calculated) aren't well-defined in documentation or tests currently,
when in doubt I tried to match the behaviour of MultiTouchInputMapper in
captured mode.

Bug: b/259547750
Test: atest inputflinger_tests
Test: use a test app to dump captured events, manually verify and
      compare with old behaviour
Change-Id: I482cce6d16ed6f947ce86e8453ddb2c9789d4d00
diff --git a/services/inputflinger/reader/Android.bp b/services/inputflinger/reader/Android.bp
index 132c3a1..b0edb57 100644
--- a/services/inputflinger/reader/Android.bp
+++ b/services/inputflinger/reader/Android.bp
@@ -42,6 +42,7 @@
         "Macros.cpp",
         "TouchVideoDevice.cpp",
         "controller/PeripheralController.cpp",
+        "mapper/CapturedTouchpadEventConverter.cpp",
         "mapper/CursorInputMapper.cpp",
         "mapper/ExternalStylusInputMapper.cpp",
         "mapper/InputMapper.cpp",